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 suffix such
as 'Jr.', 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 U.S. 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 article.
%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.
Citations
Citations have a characteristic format.
.[opening-text
flags keywords
fields
.]closing-text
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 components specify strings to
be used to bracket the label instead of those 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 behavior can be altered using the [ and ]
flags. 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.
AT&T 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.
# 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.
An advantage 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 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 commands. 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, use the non-printing input break escape sequence
\& as the first citation's closing-text.)
Commands
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 semicolons. A hash sign
(#) 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 a (neutral) double quote (") extends to the next
double quote that is not followed by another double quote. If
there is no such double quote, the word extends to the end of the
line. Pairs of double quotes in a word beginning with a double
quote collapse to a single double quote. Neither a hash sign nor
a semicolon is recognized inside double quotes. A line can be
continued by ending it with a backslash '\'; this works
everywhere except after a hash sign.
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; file 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 '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*
Accumulate references instead of writing out each
reference as it is encountered. Accumulated references
will be written out whenever a reference of the form
.[
$LIST$
.]
is encountered, after all input files have been processed,
and whenever a .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
.string
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 ...
Each string is a definite or indefinite article, and
should be ignored at the beginning of T fields when
sorting. Initially, 'a', 'an', and 'the' are recognized
as articles.
bibliography file ...
Write out all the references contained in each
bibliographic database file. This command should come
last in an .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 behavior is as
follows.
bracket-label \*([. \*(.] ", "
capitalize fields
Convert fields to caps and small caps.
compatible*
Recognize .R1 and .R2 even when followed by a character
other than space or newline.
database file ...
Search each bibliographic database file. For each file,
if an index file.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 reference.
default-database*
The default database should be searched. This is the
default behavior, 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 behavior is as
follows.
et-al " et al" 2 3
Note the absence of a dot from the end of the
abbreviation, which is arguably not correct. (Et al[.]
is short for et alli, as etc. is short for et cetera.)
include file
Include file and interpret the contents as commands.
join-authors string1 string2 string3
Join multiple authors together with strings. 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.
label-in-reference*
When outputting the reference, define the string [F to be
the reference's label. This is the default behavior, so
the negative version of this command is more useful.
label-in-text*
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
behavior, 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.
move-punctuation*
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 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-adjacent-labels*
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
field n
The n-th part of field. If n is omitted, it defaults
to 1.
'string'
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.
%n
%a
%A
%i
%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
expr-n The first (+) or last (-) n upper or lower case letters or
digits of expr. roff 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. 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.
expr.+y
The part of expr before the year, or the whole of expr if
it does not contain a year.
expr.-y
The part of expr after the year, or an empty string if
expr does not contain a year.
expr.n The last name part of expr.
expr1~expr2
expr1 except that if the last character of expr1 is - then
it will be replaced by expr2.
expr1 expr2
The concatenation of expr1 and expr2.
expr1|expr2
If expr1 is non-empty then expr1 otherwise expr2.
expr1&expr2
If expr1 is non-empty then expr2 otherwise an empty
string.
expr1?expr2:expr3
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. It is permissible for the first part to
be empty; this may be 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 register [P is set to 1 if the P
field contains a range of pages. The [T, [A and [O registers are
set to 1 according as the T, A and O fields end with any of .?!
(an end-of-sentence character). The [E 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 be 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.
