365,2422: an explanation of leap years and calendar alternatives

29 february: more on the necessity of quadrennial correction—see previously
la bougie du sapeur est sans reproche: the satirical French newspaper published only on leap days, making it the most infrequent publications in print, with its next Sunday supplement not out until 2032
intercalary days: holiday drift and other events that happen every four years
366: a scheduled agenda and play-list list how one might celebrate the day from the last time we had one—be happy that tomorrow is not 30 February
synchronoptica
four years ago: the sacrifice of the village of Elam in Plague Times
eight years ago: a vocabulary lesson, lodges of the Hakka region plus on trial for destruction of precious cultural property
twelve years ago: more quadrennial events