In two papers, N. Dershowitz and E. Reingold of the University of Illinois provide a uniform algorithmic presentation of a variety of different calendars systems, including the Gregorian, ISO, Julian, Islamic, and Hebrew calendars, as well as other calendars of historical interest. They provide Common Lisp and C++ routines to convert dates between calendars, day of the week computations, and the determination of secular and religious holidays.

The implementations of these calendars and the papers describing them are available on our local distribution site.