Provided by: groff_1.22.4-10_amd64 bug


       refer - preprocess bibliographic references for groff


       refer [-benCPRS] [-a n] [-c fields] [-f n] [-i fields] [-k field] [-l m,n] [-p filename]
             [-s fields] [-t n] -B field.macro [file ...]

       refer --help

       refer -v
       refer --version


       This file documents the GNU version  of  refer,  which  is  part  of  the  groff  document
       formatting  system.   refer  copies  the  contents  of filename... to the standard output,
       except that lines between .[ and .] are interpreted as citations, and  lines  between  .R1
       and .R2 are interpreted as commands about how citations are to be processed.

       Each  citation  specifies  a  reference.   The  citation  can  specify a reference that is
       contained in a bibliographic database by giving a set of keywords that only that reference
       contains.   Alternatively it can specify a reference by supplying a database record in the
       citation.  A combination of these alternatives is also possible.

       For each citation, refer can produce a mark in the text.  This mark consists of some label
       which  can  be  separated  from  the text and from other labels in various ways.  For each
       reference it also outputs groff commands that can be used by a macro package to produce  a
       formatted  reference  for  each citation.  The output of refer must therefore be processed
       using a suitable macro package.  The -ms and -me macros are both suitable.   The  commands
       to  format  a  citation's  reference  can be output immediately after the citation, or the
       references may be accumulated, and the commands  output  at  some  later  point.   If  the
       references  are  accumulated, then multiple citations of the same reference will produce a
       single formatted reference.

       The interpretation of lines between .R1 and .R2 as commands is a new feature of GNU refer.
       Documents  making  use of this feature can still be processed by Unix refer just by adding
       the lines

              .de R1
              .ig R2
       to the beginning of the document.  This will cause troff to ignore everything between  .R1
       and  .R2.  The effect of some commands can also be achieved by options.  These options are
       supported mainly for compatibility with Unix refer.  It is usually more convenient to  use

       refer  generates  .lf  lines  so  that  filenames and line numbers in messages produced by
       commands that read refer output will be correct; it also interprets lines  beginning  with
       .lf so that filenames and line numbers in the messages and .lf lines that it produces will
       be accurate even if the input has been preprocessed by a command such as soelim(1).


       Whitespace is permitted between a command-line option and its argument.

       Most options are equivalent  to  commands  (for  a  description  of  these  commands,  see
       subsection “Commands” below).

       -b     no-label-in-text; no-label-in-reference

       -e     accumulate

       -n     no-default-database

       -C     compatible

       -P     move-punctuation

       -S     label "(A.n|Q) ', ' (D.y|D)"; bracket-label " (" ) "; "

       -an    reverse An

              capitalize fields

       -fn    label %n

              search-ignore fields

       -k     label L~%a

              label field~%a

       -l     label A.nD.y%a

       -lm    label A.n+mD.y%a

       -l,n   label A.nD.y-n%a

       -lm,n  label A.n+mD.y-n%a

              database filename

       -sspec sort spec

       -tn    search-truncate n

       These  options  are  equivalent  to  the  following  commands  with  the addition that the
       filenames specified on the command line are processed as if they  were  arguments  to  the
       bibliography command instead of in the normal way:

       -B     annotate X AP; no-label-in-reference

              annotate field macro; no-label-in-reference

       The following options have no equivalent commands:

       -v     Print the version number.

       -R     Don't recognize lines beginning with .R1/.R2.


   Bibliographic databases
       The  bibliographic  database is a text file consisting of records separated by one or more
       blank lines.  Within each record fields start with a % at the beginning of a  line.   Each
       field  has  a  one  character name that immediately follows the %.  It is best to use only
       upper and lower case letters for the names of fields.  The name of  the  field  should  be
       followed  by  exactly  one space, and then by the contents of the field.  Empty fields are
       ignored.  The conventional meaning of each field is as follows:

       %A     The name of an author.  If the name contains a title such as Jr.  at  the  end,  it
              should  be  separated  from  the  last  name  by  a  comma.   There can be multiple
              occurrences of the %A field.  The order is significant.  It is a good  idea  always
              to supply an %A field or a %Q field.

       %B     For an article that is part of a book, the title of the book.

       %C     The place (city) of publication.

       %D     The  date  of  publication.  The year should be specified in full.  If the month is
              specified, the name rather than the number of the month should be  used,  but  only
              the  first  three  letters  are  required.  It is a good idea always to supply a %D
              field; if the date is unknown, a value such as in press or unknown can be used.

       %E     For an article that is part of a book, the name of an editor of  the  book.   Where
              the work has editors and no authors, the names of the editors should be given as %A
              fields and , (ed) or , (eds) should be appended to the last author.

       %G     US Government ordering number.

       %I     The publisher (issuer).

       %J     For an article in a journal, the name of the journal.

       %K     Keywords to be used for searching.

       %L     Label.

       %N     Journal issue number.

       %O     Other information.  This is usually printed at the end of the reference.

       %P     Page number.  A range of pages can be specified as m-n.

       %Q     The name of the author, if the author is not a person.  This will only be  used  if
              there are no %A fields.  There can only be one %Q field.

       %R     Technical report number.

       %S     Series name.

       %T     Title.   For  an  article  in  a  book  or journal, this should be the title of the

       %V     Volume number of the journal or book.

       %X     Annotation.

       For all fields except %A and %E, if there is more than  one  occurrence  of  a  particular
       field in a record, only the last such field will be used.

       If  accent  strings are used, they should follow the character to be accented.  This means
       that the AM macro must be used with the -ms macros.  Accent strings should not be  quoted:
       use one \ rather than two.

       The format of a citation is
              flags keywords

       The  opening-text,  closing-text,  and  flags  components  are  optional.  Only one of the
       keywords and fields components need be specified.

       The keywords component says to search the bibliographic databases  for  a  reference  that
       contains all the words in keywords.  It is an error if more than one reference if found.

       The fields components specifies additional fields to replace or supplement those specified
       in the reference.  When references are being accumulated and  the  keywords  component  is
       non-empty,  then  additional  fields should be specified only on the first occasion that a
       particular reference is cited, and will apply to all citations of that reference.

       The opening-text and closing-text component specifies strings to be used  to  bracket  the
       label  instead  of the strings specified in the bracket-label command.  If either of these
       components is non-empty, the strings specified in the bracket-label command  will  not  be
       used;  this  behaviour  can  be  altered  using  the [ and ] flags.  Note that leading and
       trailing spaces are significant for these components.

       The flags component is a list of non-alphanumeric characters each of  which  modifies  the
       treatment  of  this particular citation.  Unix refer will treat these flags as part of the
       keywords and so will ignore them since they are non-alphanumeric.  The following flags are
       currently recognized:

       #      This  says  to  use the label specified by the short-label command, instead of that
              specified by the label command.  If no short label has been specified,  the  normal
              label  will be used.  Typically the short label is used with author-date labels and
              consists of only the date and possibly a disambiguating letter; the #  is  supposed
              to be suggestive of a numeric type of label.

       [      Precede opening-text with the first string specified in the bracket-label command.

       ]      Follow closing-text with the second string specified in the bracket-label command.

       One  advantages  of using the [ and ] flags rather than including the brackets in opening-
       text and closing-text is that you can change the style of bracket  used  in  the  document
       just by changing the bracket-label command.  Another advantage is that sorting and merging
       of citations will not necessarily be inhibited if the flags are used.

       If a label is to be inserted into the text, it will be attached to the line preceding  the
       .[ line.  If there is no such line, then an extra line will be inserted before the .[ line
       and a warning will be given.

       There is no special notation for making a citation to multiple  references.   Just  use  a
       sequence  of citations, one for each reference.  Don't put anything between the citations.
       The labels for all the citations  will  be  attached  to  the  line  preceding  the  first
       citation.   The  labels may also be sorted or merged.  See the description of the <> label
       expression, and of the sort-adjacent-labels and abbreviate-label-ranges command.  A  label
       will not be merged if its citation has a non-empty opening-text or closing-text.  However,
       the labels for a citation using the  ]  flag  and  without  any  closing-text  immediately
       followed  by  a  citation  using the [ flag and without any opening-text may be sorted and
       merged even though the first citation's opening-text or the second citation's closing-text
       is  non-empty.   (If  you wish to prevent this just make the first citation's closing-text

       Commands are contained between lines starting with .R1  and  .R2.   Recognition  of  these
       lines  can  be  prevented by the -R option.  When a .R1 line is recognized any accumulated
       references are flushed out.  Neither .R1 nor .R2  lines,  nor  anything  between  them  is

       Commands  are separated by newlines or ;s.  # introduces a comment that extends to the end
       of the line (but does not conceal the newline).  Each command is  broken  up  into  words.
       Words  are  separated  by spaces or tabs.  A word that begins with " extends to the next "
       that is not followed by another ".  If there is no such " the word extends to the  end  of
       the  line.  Pairs of " in a word beginning with " collapse to a single ".  Neither # nor ;
       are recognized inside "s.  A line can be  continued  by  ending  it  with  \;  this  works
       everywhere except after a #.

       Each  command  name  that is marked with * has an associated negative command no-name that
       undoes the effect of name.  For example, the no-sort  command  specifies  that  references
       should not be sorted.  The negative commands take no arguments.

       In  the  following  description  each  argument must be a single word; field is used for a
       single upper or lower case letter naming a field; fields is used for a  sequence  of  such
       letters;  m  and  n  are  used for a non-negative numbers; string is used for an arbitrary
       string; filename is used for the name of a file.

       abbreviate* fields string1 string2 string3 string4
              Abbreviate the first names of fields.  An initial letter  will  be  separated  from
              another initial letter by string1, from the last name by string2, and from anything
              else (such as a von or de) by string3.  These default to a  period  followed  by  a
              space.   In a hyphenated first name, the initial of the first part of the name will
              be separated from the hyphen by string4; this defaults to a period.  No attempt  is
              made  to  handle  any  ambiguities  that might result from abbreviation.  Names are
              abbreviated before sorting and before label construction.

       abbreviate-label-ranges* string
              Three or more  adjacent  labels  that  refer  to  consecutive  references  will  be
              abbreviated  to  a label consisting of the first label, followed by string followed
              by the last label.  This is mainly  useful  with  numeric  labels.   If  string  is
              omitted it defaults to -.

              Accumulate  references  instead of writing out each reference as it is encountered.
              Accumulated references will be written out whenever a reference of the form


              is encountered, after all input files have been processed, and whenever .R1 line is

       annotate* field string
              field  is  an  annotation;  print  it  at  the  end of the reference as a paragraph
              preceded by the line


              If string is omitted it will default to AP;  if  field  is  also  omitted  it  will
              default to X.  Only one field can be an annotation.

       articles string...
              string...  are  definite  or  indefinite  articles,  and  should  be ignored at the
              beginning of T fields when sorting.  Initially, the, a and  an  are  recognized  as

       bibliography filename...
              Write  out  all the references contained in the bibliographic databases filename...
              This command should come last in a .R1/.R2 block.

       bracket-label string1 string2 string3
              In the text, bracket each label with string1 and string2.  An occurrence of string2
              immediately followed by string1 will be turned into string3.  The default behaviour

                     bracket-label \*([. \*(.] ", "

       capitalize fields
              Convert fields to caps and small caps.

              Recognize .R1 and .R2 even when  followed  by  a  character  other  than  space  or

       database filename...
              Search  the  bibliographic  databases  filename...   For  each filename if an index
              filename.i created by indxbib(1) exists, then it will  be  searched  instead;  each
              index can cover multiple databases.

       date-as-label* string
              string  is  a  label expression that specifies a string with which to replace the D
              field after constructing the label.  See subsection “Label expressions” below for a
              description  of  label  expressions.   This  command  is  useful if you do not want
              explicit labels in the reference list, but instead want  to  handle  any  necessary
              disambiguation  by  qualifying  the  date  in some way.  The label used in the text
              would typically be some combination of the author and  date.   In  most  cases  you
              should also use the no-label-in-reference command.  For example,

                     date-as-label D.+yD.y%a*D.-y

              would  attach  a  disambiguating  letter  to  the  year  part of the D field in the

              The default database should be searched.  This is the  default  behaviour,  so  the
              negative  version  of  this  command  is more useful.  refer determines whether the
              default database should be searched on the first occasion that it  needs  to  do  a
              search.   Thus a no-default-database command must be given before then, in order to
              be effective.

       discard* fields
              When the reference is read, fields should be discarded; no string  definitions  for
              fields will be output.  Initially, fields are XYZ.

       et-al* string m n
              Control  use  of et al in the evaluation of @ expressions in label expressions.  If
              the number of authors needed to make the author sequence unambiguous is u  and  the
              total  number  of authors is t then the last t-u authors will be replaced by string
              provided that t-u is not less than m and  t  is  not  less  than  n.   The  default
              behaviour is

                     et-al " et al" 2 3

       include filename
              Include filename and interpret the contents as commands.

       join-authors string1 string2 string3
              This  says  how  authors  should  be  joined  together.  When there are exactly two
              authors, they will be joined with string1.  When there are more than  two  authors,
              all  but the last two will be joined with string2, and the last two authors will be
              joined with string3.  If string3 is omitted, it will default to string1; if string2
              is also omitted it will also default to string1.  For example,

                     join-authors " and " ", " ", and "

              will restore the default method for joining authors.

              When  outputting  the  reference, define the string [F to be the reference's label.
              This is the default behaviour; so the negative version  of  this  command  is  more

              For  each  reference  output a label in the text.  The label will be separated from
              the surrounding text as described  in  the  bracket-label  command.   This  is  the
              default behaviour; so the negative version of this command is more useful.

       label string
              string is a label expression describing how to label each reference.

       separate-label-second-parts string
              When merging two-part labels, separate the second part of the second label from the
              first label with string.  See the description of the <> label expression.

              In the text, move any punctuation at the end of line past the label.  It is usually
              a  good  idea  to  give  this command unless you are using superscripted numbers as

       reverse* string
              Reverse the fields whose names are in string.  Each field name can be followed by a
              number  which  says how many such fields should be reversed.  If no number is given
              for a field, all such fields will be reversed.

       search-ignore* fields
              While searching for keys in  databases  for  which  no  index  exists,  ignore  the
              contents of fields.  Initially, fields XYZ are ignored.

       search-truncate* n
              Only  require the first n characters of keys to be given.  In effect when searching
              for a given key words in the database are truncated to the maximum  of  n  and  the
              length of the key.  Initially n is 6.

       short-label* string
              string  is a label expression that specifies an alternative (usually shorter) style
              of label.  This is used when the # flag is  given  in  the  citation.   When  using
              author-date  style labels, the identity of the author or authors is sometimes clear
              from the context, and so it may be desirable to omit the author or authors from the
              label.   The  short-label  command  will  typically  be  used  to  specify  a label
              containing just a date and possibly a disambiguating letter.

       sort* string
              Sort references according to string.  References will automatically be accumulated.
              string  should  be a list of field names, each followed by a number, indicating how
              many fields with the name should be used for sorting.  + can be  used  to  indicate
              that  all  the fields with the name should be used.  Also . can be used to indicate
              the references should be sorted using the (tentative)  label.   (Subsection  “Label
              expressions” below describes the concept of a tentative label.)

              Sort  labels  that  are  adjacent  in  the  text according to their position in the
              reference list.  This command should usually  be  given  if  the  abbreviate-label-
              ranges command has been given, or if the label expression contains a <> expression.
              This will have no effect unless references are being accumulated.

   Label expressions
       Label expressions can be evaluated both normally and tentatively.  The  result  of  normal
       evaluation  is  used for output.  The result of tentative evaluation, called the tentative
       label, is used to gather the information that normal evaluation needs to disambiguate  the
       label.   Label expressions specified by the date-as-label and short-label commands are not
       evaluated tentatively.  Normal and tentative evaluation are the  same  for  all  types  of
       expression  other  than  @, *, and % expressions.  The description below applies to normal
       evaluation, except where otherwise specified.

       field n
              The n-th part of field.  If n is omitted, it defaults to 1.

              The characters in string literally.

       @      All the authors joined as specified by the join-authors command.  The whole of each
              author's  name will be used.  However, if the references are sorted by author (that
              is the sort specification starts with A+), then authors last  names  will  be  used
              instead,  provided  that  this  does  not  introduce ambiguity, and also an initial
              subsequence of the authors may be used instead of all the authors,  again  provided
              that this does not introduce ambiguity.  The use of only the last name for the i-th
              author of some reference is considered to be  ambiguous  if  there  is  some  other
              reference, such that the first i-1 authors of the references are the same, the i-th
              authors are not the same, but the i-th authors last names are the same.   A  proper
              initial  subsequence of the sequence of authors for some reference is considered to
              be ambiguous if there is a reference with some other sequence of authors which also
              has  that subsequence as a proper initial subsequence.  When an initial subsequence
              of authors is used, the remaining authors are replaced by the string  specified  by
              the  et-al command; this command may also specify additional requirements that must
              be met before an initial subsequence can be used.  @  tentatively  evaluates  to  a
              canonical representation of the authors, such that authors that compare equally for
              sorting purpose will have the same representation.

       %I     The serial number of the reference formatted according to the  character  following
              the %.  The serial number of a reference is 1 plus the number of earlier references
              with same  tentative  label  as  this  reference.   These  expressions  tentatively
              evaluate to an empty string.

       expr*  If there is another reference with the same tentative label as this reference, then
              expr, otherwise an empty string.  It tentatively evaluates to an empty string.

       expr-n The first (+) or last (-) n upper or lower case letters or digits of  expr.   Troff
              special  characters  (such  as  \('a) count as a single letter.  Accent strings are
              retained but do not count towards the total.

       expr.l expr converted to lowercase.

       expr.u expr converted to uppercase.

       expr.c expr converted to caps and small caps.

       expr.r expr reversed so that the last name is first.

       expr.a expr with first names abbreviated.  Note that fields specified  in  the  abbreviate
              command  are  abbreviated  before any labels are evaluated.  Thus .a is useful only
              when you want a field to be abbreviated in a label but not in a reference.

       expr.y The year part of expr.

              The part of expr before the year, or the whole of expr if it  does  not  contain  a

              The  part  of  expr  after  the year, or an empty string if expr does not contain a

       expr.n The last name part of expr.

              expr1 except that if the last character of expr1 is - then it will be  replaced  by

       expr1 expr2
              The concatenation of expr1 and expr2.

              If expr1 is non-empty then expr1 otherwise expr2.

              If expr1 is non-empty then expr2 otherwise an empty string.

              If expr1 is non-empty then expr2 otherwise expr3.

       <expr> The  label  is  in  two  parts, which are separated by expr.  Two adjacent two-part
              labels which have the same first part will be merged by appending the  second  part
              of  the  second label onto the first label separated by the string specified in the
              separate-label-second-parts command (initially, a comma followed by a  space);  the
              resulting  label  will  also be a two-part label with the same first part as before
              merging, and so additional  labels  can  be  merged  into  it.   Note  that  it  is
              permissible  for  the  first part to be empty; this maybe desirable for expressions
              used in the short-label command.

       (expr) The same as expr.  Used for grouping.

       The above expressions are listed in order of precedence (highest first); & and | have  the
       same precedence.

   Macro interface
       Each  reference  starts  with a call to the macro ]-.  The string [F will be defined to be
       the label for this reference, unless the no-label-in-reference  command  has  been  given.
       There  then  follows  a  series  of  string  definitions,  one  for  each field: string [X
       corresponds to field X.  The number register [P is set to 1 if  the  P  field  contains  a
       range of pages.  The [T, [A and [O number registers are set to 1 according as the T, A and
       O fields end with one of the characters .?!.  The [E number register will be set  to 1  if
       the  [E string contains more than one name.  The reference is followed by a call to the ][
       macro.  The first argument to this macro gives a  number  representing  the  type  of  the
       reference.   If a reference contains a J field, it will be classified as type 1, otherwise
       if it contains a B field, it will type 3, otherwise if it contains a G or R field it  will
       be  type 4,  otherwise  if  it contains an I field it will be type 2, otherwise it will be
       type 0.  The second argument is a symbolic name  for  the  type:  other,  journal-article,
       book,  article-in-book or tech-report.  Groups of references that have been accumulated or
       are produced by the bibliography command are preceded by  a  call  to  the  ]<  macro  and
       followed by a call to the ]> macro.


              Default database.

       file.i Index files.

       refer  uses  temporary  files.  See the groff(1) man page for details where such files are


       REFER  If set, overrides the default database.


       indxbib(1), lookbib(1), lkbib(1)


       In label expressions, <> expressions are ignored inside .char expressions.