Formatting entries

As of the winter 1992 release, the bibliography has been converted to bibtex. Up to this time the bibliography had (for historical reasons) been more or less in the format of the old "refer" program designed as a citation system for troff. Special thanks to volunteers Jeff Erickson, Robert Freimer, and Peter Yamamoto, who took the initiative of developing quality conversion software to meet our situation.

Because of the distributed nature of updates, it seems desirable to have some written guidelines for the format of entries, in order that the final product have a consistent style. The following suggestions are based on common practice where discernible, established authorities where possible, and personal opinion where unavoidable.

You will likely find existing entries in disagreement with these guidelines. Either the entry or the guidelines should be fixed. If some entry can't be decently handled by the current guidelines, or you think they're just plain wrong in any case, please let us know about it.

In the hope of keeping future input work reasonably simple and error-free, a few lexical conventions were set at the time of bibtex conversion, as follows. Where possible you should use lower case (for simplicity), a leading comma ", volume = 12" (to make missing commas obvious), and put all text for a field on a single line (to avoid spending time on prettyprinting). If you must break lines, such as in the abstract= or annote= or comments= or note= fields, start subsequent lines with a tab.

Special characters and diacriticals should be entered as specified on p.52 of the TeXbook. The common single-letter ones are described below.

   \'  acute           sup{\'e}rieur    {\'O}'D{\'u}nlaing   [\*' in troff -ms]
   \`  grave           probl{\`e}me     Bruy{\`e}re          [\*` in troff -ms]
   \^  circumflex      m{\^e}me         L'H{\^o}pital        [\*' in troff -ms]
   \~  tilde           ma{\~n}ana       N{\'u}{\~n}ez        [\*' in troff -ms]
   \v  hacek           h{\'a}{\v c}ek   Matou{\v s}ek        [\*C in troff -ms]
   \c  cedilla         fran{\c c}ais    {\'S}wi{\c a}tek     [\*, in troff -ms]
   \"  umlaut          f{\"u}r          G{\"u}ting           [\*: in troff -ms]
   \H  Hung. umlaut                     Erd{\H o}s           [R.I.P. 96.09.20]
   \i  dotless i                        D{\'\i}az            where accented
   \j  dotless j                                             where accented
Note that diacriticals precede the letter affected. A complication is that in tex, control sequences specified using letters must somehow be separated from the ordinary letters that follow. A simple way is to use spaces as in "Erd\H os", but this will look like two separate words to bibtex. Another is to use braces as in "Erd\H{o}s", but this too is confounded by bibtex, which (1) normally wants to decapitalize text in titles not protected by braces, to support variant capitalization styles, and (2) will interpret an umlaut \" as the end of a quoted string, unless specially protected.

Initially it might seem enough to put braces around the whole word when it contains either a fussy diacritical or (in a title field) a capital letter. However, it turns out that, because of how it handles the author field, bibtex dictates the convention to follow. Since adding a feature to recognize and handle accented characters in author fields (for benefit of the alpha bibliography styles), bibtex requires that we "place the entire accented character in braces; in this case either {\"o} or {\"{o}} will do .... furthermore these braces must not themselves be enclosed in braces (other than the ones that might delimit the entire field or the entire entry), and there must be a backslash as the very first character inside the braces". Thus you should use, for example, {\'O}'D{\'u}nlaing, Matou{\v s}ek, G{\"u}ting, and Erd{\H o}s, and we recommend that for consistency you treat all accents this way in whatever bibtex fields they appear. However you will further have to embrace the whole of any capitalized name that appears in a title field. C'est la vie {BibTeXienne}.

A few hacks deserve mention. The macro \path, from path.sty, helps with transparency and linebreaking of network pathnames like \path||, and should be used whenever they appear in regular text. (path.sty is part of the Eplain package, and is being used when typesetting the url field for Tex ties like ~ and "\ " should be avoided in regular text, as bibtex undertakes to insert them where appropriate.

Mathematical expressions, including numbers in titles, should always be entered in tex notation. Author, title, and page information from other than the title page of the paper itself is untrustworthy: you might want to do data entry from a proceedings table of contents for speed, but please take time to proofread against title pages for accuracy.

Below is a quick naming of parts for entries in the database, with discussions of the conventions that have evolved. More detailed information on entry formats can be found in the bibtex documentation.

Entry type:

We ignore some of the fine distinctions available in bibtex and map most everything onto the types of article, book, inbook, incollection, inproceedings, mastersthesis, phdthesis, and techreport. Preprints (a.k.a. "Manuscripts") are considered unnumbered techreports for our purposes, since they are often later distributed in that form. If present entries in the bibliography are any guide, you should rarely need other entry types. In particular, note that low-grade items like personal communications should not be included since our charter is to cover only openly available materials. If you need such an entry in your papers' reference lists, please keep it in a supplementary bibliography file until it is published. For example, "\bibliography{mine,mygroup,geom}" specifies a search path of three files bibtex can use to satisfy references.

Citation tag:

It's easy to come up with citetags that are mnemonic, short, or unique, but not to have all three at the same time. The system we use is a compromise. Our citetags consist of an author part (first letter of surname of each author), a title part (first letter or digit string of each significant word in the title, up to 5 characters), and a year part (last two digits of year of publication), separated by dashes. Connecting words like auf, da, de, der, van, von are considered part of the surname if and only if they are capitalized. Thus "J. O'Rourke, Art Gallery Theorems and Algorithms, 1987" reduces to "o-agta-87". The tricky part of this is how to define "significant" words of the title, particularly when punctuation and mathematical strings are involved. Here are the formal rules, which are intended to produce a commonsense result as often as possible: For example, "fran{\c c}ais" and "$\log n-1$" are each one word while "$k$th-nearest" is two, and the abbreviation of "{${\rm SEPARATION}^{\rm TM}$} and $(\leq k)$-levels IV: A silly example" is "sll4s".

To make the result more intuitive, we break the rules in the following cases:

For just under 99% of entries the citetag generated by this procedure will not conflict with that of any existing entry. But if it does, you'll have to find some way to break the tie. In our experience, collisions at this stage have come about only from various forms of the ``same paper'' conflicting with each other, and one of the following tiebreaking rules suffices: If the resulting citetags don't match your favourite descriptor for the reference, you can still use the old familiar version if you declare a mapping between the two in your tex source, such as the following:
Entry citetags should be mostly stable once assigned, but may be changed in the direction of correctness, or to resolve conflicts. You needn't bother creating citetags for entries you don't cite: just leave the tag part empty. The merging software will automatically generate citetags for contributed entries lacking them. It also rewrites conference and journal names to standard form, does prettyprinting, and keeps entries in the geom.bib file sorted in order of author, title, and year, all the better to bring various appearances of the same paper together. (This should match the order of the default softcopy.)


We inherit most fields from the bibtex standard styles, as well as common extensions like abstract=, annote=, isbn=, language=. Fields cites=, comments=, keywords=, precedes=, succeeds=, update=, and url= are our own. Conventions for entering all of these are as follows. Quotes aren't necessary when the field value is entirely digits (true for volume, number, and year, normally). You should use the empty string "" for fields you can't complete just yet (e.g., pages = "" for a conference or journal paper to appear). Some older entries use a visible placeholder like "??"; if you need to cite them, please make an honest effort to fill the hole rather than immediately changing to "".