He would be very interested into any pointers of the history of these three date notations, and actually I am quite interested as well. Why do Americans write dates as "December 31, 1999" while Europeans write "31 December 1999", etc.? Why are in East Asia Bigendian dates more common?

I wouldn't know the why, but Hungary is also bigendian. Not so surprising, in the names the christian name also follows the family name, so you have the "Street Chopin Frederic" (loosely translated). dik -- dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland, +31205924131 home: bovenover 215, 1025 jn amsterdam, nederland; http://www.cwi.nl/~dik/