Thanks for posting ISO/FDIS 8601:2000. Looks at first glance like a good revision of the standard to me. For section 3.11, it would be nice to have a proper normative reference added for the "Gregorian Calendar". After all, the Vatican has been far longer around and is far more widely known than ISO/ITU/IERS/BIPM and other churches of bureaucracy all together, and like any other standards body it also publishes normative formal documents, so why not reference it properly? Does anyone have the proper reference? If I remember correctly (it has been a long time), Pope Gregory XIII published back in 1582 three official documents: a bulletin that explained the reform, a calendar and a revised list of religious holidays. Also a reference for the Julian calendar? http://www.vatican.va/ http://www.vatican.va/library_archives/vat_library/docs/index.htm http://www.gksoft.com/govt/en/va.html I like that section 4.3.2.1 defines the "prolaptic Gregorian calendar" to have a year 0000, which is a leap year, and that ISO 8601 now has provisions for years outside the 0000 to 9999 range. Markus -- Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK Email: mkuhn at acm.org, WWW: <http://www.cl.cam.ac.uk/~mgk25/>