Entry Format

BibTeX database files (extension .bib) are plain text files. They consist of entries of various kinds. Each entry describes a book, an article, a manual, etc. Example:

     AUTHOR = "Donald E. Knudson",
     TITLE = "1966 World Gnus Almanac",
     PUBLISHER = {Permafrost Press},
     ADDRESS = {Novosibirsk}

The @BOOK states that this is an entry of type book. Various entry types are described below. The kn:gnus is the cite key, as it appears in the argument of a \cite command referring to the entry.

This entry has four fields, named AUTHOR, TITLE, PUBLISHER, and ADDRESS. The meanings of these and other fields are described below. A field consists of the name, followed by an "=" character with optional space around it, followed by its text. The text of a field is a string of characters, with no unmatched braces, surrounded by either a pair of braces or a pair of " characters. Entry fields are separated from one another, and from the key, by commas. A comma may have optional space around it.

The outermost braces that surround the entire entry may be replaced by parentheses. An end-of-line character counts as a space and one space is equivalent to one hundred (as in LaTeX). BibTeX ignores the case of letters in the entry type, cite key, and field names.

The quotes or braces can be omitted around text consisting entirely of numerals: Volume = "27" is equivalent to Volume = 27.

Entry Fields

When entering a reference in the database, the first thing to decide is what type of entry it is. No fixed classification scheme can be complete, but BibTeX provides enough entry types to handle almost any reference reasonably well.

References to different types of publications contain different information; a reference to a journal article might include the volume and number of the journal, which is usually not meaningful for a book. Therefore, database entries of different types have different fields. For each entry type, the fields are divided into three classes:

Omitting the field will produce a warning message and, rarely, a badly formatted bibliography entry. If the required information is not meaningful, you are using the wrong entry type. However, if the required information is meaningful but, say, already included is some other field, simply ignore the warning.
The field's information will be used if present, but can be omitted without causing any formatting problems. You should include the optional field if it will help the reader.
The field is ignored. BibTeX ignores any field that is not required or optional, so you can include any fields you want in a bib file entry. It's a good idea to put all relevant information about a reference in its bib file entry--even information that may never appear in the bibliography. For example, if you want to keep an abstract of a paper in a computer file, put it in an abstract field in the paper's bib file entry. The bib file is likely to be as good a place as any for the abstract, and it is possible to design a bibliography style for printing selected abstracts. Note: Misspelling a field name will result in its being ignored, so watch out for typos (especially for optional fields, since BibTeX won't warn you when those are missing).

Entry Types

The following are the standard entry types, along with their required and optional fields, that are used by the standard bibliography styles. The fields within each class (required or optional) are listed in order of occurrence in the output, except that a few entry types may perturb the order slightly, depending on what fields are missing. These entry types are similar to those adapted by Brian Reid from the classification scheme of van Leunen  for use in the Scribe system. The meanings of the individual fields are explained in the next section. Some nonstandard bibliography styles may ignore some optional fields in creating the reference. Remember that, when used in the bib file, the entry-type name is preceded by an @ character.

An article from a journal or magazine. Required fields: author, title, journal, year. Optional fields: volume, number, pages, month, note.
A book with an explicit publisher. Required fields: author or editor, title, publisher, year. Optional fields: volume or number, series, address, edition, month, note.
A work that is printed and bound, but without a named publisher or sponsoring institution. Required field: title. Optional fields: author, howpublished, address, month, year, note.
The same as inproceedings, included for Scribe compatibility.
A part of a book, which may be a chapter (or section or whatever) and/or a range of pages. Required fields: author or editor, title, chapter and/or pages, publisher, year. Optional fields: volume or number, series, type, address, edition, month, note.
A part of a book having its own title. Required fields: author, title, booktitle, publisher, year. Optional fields: editor, volume or number, series, type, chapter, pages, address, edition, month, note.
An article in a conference proceedings. Required fields: author, title, booktitle, year. Optional fields: editor, volume or number, series, pages, address, month, organization, publisher, note.
Technical documentation. Required field: title. Optional fields: author, organization, address, edition, month, year, note.
A Master's thesis. Required fields: author, title, school, year. Optional fields: type, address, month, note.
Use this type when nothing else fits. Required fields: none. Optional fields: author, title, howpublished, month, year, note.
A PhD thesis. Required fields: author, title, school, year. Optional fields: type, address, month, note.
The proceedings of a conference. Required fields: title, year. Optional fields: editor, volume or number, series, address, month, organization, publisher, note.
A report published by a school or other institution, usually numbered within a series. Required fields: author, title, institution, year. Optional fields: type, number, address, month, note.
A document having an author and title, but not formally published. Required fields: author, title, note. Optional fields: month, year.

In addition to the fields listed above, each entry type also has an optional key field, used in some styles for alphabetizing, for cross referencing, or for forming a \bibitem label. You should include a key field for any entry whose "author" information is missing; the "author" information is usually the author field, but for some entry types it can be the editor or even the organization field. Do not confuse the key field with the citekey that appears in the \cite command and at the beginning of the database entry; this field is named "key" only for compatibility with Scribe.

BibTeX recognizes two more fields not mentioned above. The annote field can be used to produce an annotated bibliography. The crossref field can be used for cross-referencing between entries; see the LaTeX manual for details.

Bibtex.php uses some extra fields. The keywords field is used to assign one or more keywords to the entry that can be used to group entries into subject areas or bibliographies. The url field is typically used to point to the actual paper on the web. Both keywords and url can have multiple values, which must be entered on separate lines in the bibtex.php interface, or comma separated in the bib file. The abstract field can be used to keep the abstract of a paper. You can include any other fields you want in an entry, bibtex.php will keep them in its database, and BibTeX will ignore them when typesetting a bibliography.

Finally, entrytype, which is used to classify entries, and citekey, which is used for referencing an entry, are not fields in the above sense, but appear as such in the bibtex.php interface.


Below is a description of all fields recognized by the standard bibliography styles. An entry can also contain other fields, which are ignored by those styles.

Usually the address of the publisher or other type of institution. For major publishing houses, van Leunen recommends omitting the information entirely. For small publishers, on the other hand, you can help the reader by giving the complete address.
An annotation. It is not used by the standard bibliography styles, but may be used by others that produce an annotated bibliography.
The name(s) of the author(s), in the format described in the Names section.
Title of a book, part of which is being cited. See the Titles section for how to type titles. For book entries, use the title field instead.
A chapter (or section or whatever) number.
The database key of the entry being cross referenced.
The edition of a book--for example, "Second". This should be an ordinal, and should have the first letter capitalized, as shown here; the standard styles convert to lower case when necessary.
Name(s) of editor(s), typed as indicated in the Names section. If there is also an author field, then the editor field gives the editor of the book or collection in which the reference appears.
How something strange has been published. The first word should be capitalized.
The sponsoring institution of a technical report.
A journal name.
Used for alphabetizing, cross referencing, and creating a label when the "author" information is missing. This field should not be confused with the key that appears in the \cite command and at the beginning of the database entry.
The month in which the work was published or, for an unpublished work, in which it was written. You should use the standard three-letter abbreviation, as described in Appendix B.1.3 of the LaTeX book.
Any additional information that can help the reader. The first word should be capitalized.
The number of a journal, magazine, technical report, or of a work in a series. An issue of a journal or magazine is usually identified by its volume and number; the organization that issues a technical report usually gives it a number; and sometimes books are given numbers in a named series.
The organization that sponsors a conference or that publishes a manual.
One or more page numbers or range of numbers, such as 42-111 or 7,41,73-97 or 43+ (the "+" in this last example indicates pages following that don't form a simple range). To make it easier to maintain Scribe-compatible databases, the standard styles convert a single dash (as in 7-33) to the double dash used in TEX to denote number ranges (as in 7-33).
The publisher's name.
The name of the school where a thesis was written.
The name of a series or set of books. When citing an entire book, the the title field gives its title and an optional series field gives the name of a series or multi-volume set in which the book is published.
The work's title, typed as explained in the Titles section.
The type of a technical report--for example, "Research Note".
The volume of a journal or multivolume book.
The year of publication or, for an unpublished work, the year it was written. Generally it should consist of four numerals, such as 1984, although the standard styles can handle any year whose last four nonpunctuation characters are numerals, such as "(about 1984)".


The text of an author or editor field represents a name. In bibtex.php, multiple names should be entered on separate lines. They will be joined using "and" in the BibTeX output. The bibliography style determines how the names are printed: whether the first name or last name appears first, if the full first name or just the first initial is used, etc. Most names can be entered in the obvious way, i.e., "John Paul Jones" or "Jones, John Paul". However, only the second form, with a comma, should be used for people who have last names with multiple parts that are capitalized. People with a "Jr." in their name should be entered as "Ford, Jr., Henry".

If an entry has more names than you want to type, just end the list of names with "others"; the standard styles convert this to the conventional et al. For foreign names with accented characters, please refer to the Non-English characters section.


The bibliography style determines whether or not a title is capitalized; the titles of books usually are, the titles of articles usually are not. You type a title the way it should appear if it is capitalized.

     title = "The Agony and the Ecstasy"

You should capitalize the first word of the title, the first word after a colon, and all other words except articles and unstressed conjunctions and prepositions. BibTeX will change uppercase letters to lowercase if appropriate. Uppercase letters that should not be changed are enclosed in braces. The following two titles are equivalent; the A of Africa will not be made lowercase.

     "The Gnats and Gnus of {Africa}"
     "The Gnats and Gnus of {A}frica"

Non-English Characters

Bibtex.php does not currently support non-ascii characters. To enter foreign characters you need to use LaTeX escape sequences described below. BibTeX is sometimes confused by these sequences, but it will do the right thing if you put curly braces immediately around the sequence, e.g. {\"{o}} or {\"o} will work.

The following accents may be placed on letters. Although "o" is used in most of the examples, the accents may be placed on any letter. Accents may even be placed above a "missing" letter; for example, \~{} produces a tilde over a blank space.

\`{o}: ò \^{o}: ô \"{o}: ö \={o}: ō \.{c}: ċ \i: ı \~{o}: õ \u{o}: ŏ
\'{o}: ó \v{s}: š \H{o}: ő \b{o}: o \d{s}: ṣ \.{I}: İ \c{c}: ç \t{oo}: o͡o

Note that the letters "i" and "j" require special treatment when they are given accents because it is often desirable to replace the dot with the accent. For this purpose, the commands \i and \j can be used to produce dotless letters. For example, \^{\i} should be used for i circumflex: î, and \"{\i} should be used for i umlaut: ï.

Other characters and symbols:

\ae: æ \oe: œ \aa: å \o: ø \l: ł ?` or >: ¿ \dag: † \S: § \copyright: © \ss: ß
\AE: Æ \OE: Œ \AA: Å \O: Ø \L: Ł !` or <: ¡ \ddag: ‡ \P: ¶ \pounds: £

In addition, the following seven symbols need to be escaped with a backslash: \#, \$, \%, \&, \_, \{, \}.


Sheldon Green 1995: Hypertext Help with LaTeX. http://www.giss.nasa.gov/tools/latex.

Dana Jacobsen 1996: BibTeX. http://www.ecst.csuchico.edu/~jacobsd/bib/formats/bibtex.html.

Leslie Lamport 1994: LaTeX: A Document Preparation System. User's Guide and Reference Manual. Second Edition. Addison-Wesley, November 1994. Appendix B.

Oren Patashnik 1988: BibTeXing. The documentation for BibTeX version 0.99b. http://www.denizyuret.com/ref/patashnik/btxdoc.html.

Oren Patashnik 1988: Designing BibTeX Styles. Documentatio for bibliography style writers. http://www.denizyuret.com/ref/patashnik/btxhak.html.

Urs-Jakob Rüetschi 2003: The BibTeX Bibliography Database. http://www.geo.unizh.ch/~uruetsch/varia/bibtex.html.

CTAN, the Comprehensive TeX Archive Network, URL http://www.ctan.org/.

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