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:
- 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
- For an article that is part of a book, the title of the book.
- The place (city) of publication.
- 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.
- 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.
- US Government ordering number.
- The publisher (issuer).
- For an article in a journal, the name of the journal.
- Keywords to be used for searching.
- Journal issue number.
- Other information. This is usually printed at the end of the
- Page number. A range of pages can be specified as
- 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
- Technical report number.
- Series name.
- Title. For an article in a book or journal, this should be the title of
- Volume number of the journal or book.
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
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
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
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
- 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
- Follow closing-text with the second string specified in the
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
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
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 output.
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
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
- 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 recognized.
- 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 articles.
- bibliography filename...
- Write out all the references contained in the bibliographic databases
filename... This command should come last in a
- 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 is
- 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 newline.
- database filename...
- Search the bibliographic databases filename... For each
filename if an index filename.i created by
gindxbib(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
- date-as-label D.+yD.y%a*D.-y
would attach a disambiguating letter to the year part of the
D field in the reference.
- 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
- 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
- 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
- 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 useful.
- 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
- 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 labels.
- 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
- search-ignore* fields
- While searching for keys in databases for which no index exists, ignore
the contents of fields. Initially, fields XYZ are
- 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
- 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
- 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.