The logical structure of a bibliographic reference shows what can be and what should be in a reference. Here is an example of a reference content, that follows a logical structure (the BibTeX structure, and a reference of type article):
@ARTICLE{joseph92a,
AUTHOR = {S. H. Joseph and T. P. Pridmore},
TITLE = {Knowledge-Directed Interpretation of Mechanical
Engineering Drawings},
JOURNAL = {IEEE Transactions on PAMI},
YEAR = {1992},
NUMBER = {9},
VOLUME = {14},
PAGES = {211--222},
MONTH = {September},
KEYWORDS = {segmentation, forms},
ABSTRACT = {The approach is based on item extraction}
}
Each type of reference (also called entry in a BibTeX database) contains specific information: an article as the one above can use fields (as volume and number) that are meaningless in other reference types (as phdthesis or masterthesis).
Three field classes exist: required, optional, and ignored (in the case of BibTeX). In the sample above, the keyword field will be ignored in the physical version of the reference.
The LaTeX Companion gives those two fields list of two different entry types:
- article
- a journal article. Required fields: author, title, journal, year. Optional fields: volume, number, pages, month, note. Other fields are ignored.
- inproceedings
- articles from the proceedings of a conference. Required fields: author, title, booktitle, year. Optional fields: editor, pages, organization, publisher, address, month, note.
Each entry also has a unique key, different from those of the other entries in the database (in the example, it's joseph92a.
Other types of reference (in BibTeX) are: book, booklet (printed document, without publisher or institution), inbook (part of a book, a chapter and/or a pages interval), incollection (part of a book with its proper title), manual, misc (for miscellaneous, to be used when no other type matches), phdthesis, proceedings, techreport, unpublished.
The difficulty for an author is often in the choice of the reference's type, and in the choice of the fields to use. Some users tend to use the misc type for all entries and/or to merge different fields into only one.
Remark: BibTeX's logical structure has only one level (on the contrary to ISBD). For example, title contains only text, no matter what. ISBD's title can contain a proper title, a parallel title, a sub-title etc. But BibTeX fields implicitly have sub-fields: authors, in the author fields are separated by "and" (this is required).