*Mental calculation==References====External links==*Encyclopedia of Weekday Calculation by Hans-Christian Solka, 2010* Doomsday calculator that also "shows all work"* World records for mentally calculating the day of the week in the Gregorian Calendar* What is the day of the week, given any date?
ISBN 0-120-91102-7== Ссылки ==* Lewis Carroll’s 1887 Weekday Rule, 2011* COWAFOGO • Weekday Solving Simplified, 2011* Encyclopedia of Weekday Calculation by Hans-Christian Solka, 2010* Doomsday calculator that also «shows all work»* World records for mentally calculating the day of the week in the Gregorian Calendar* What is the day of the week, given any date?