There are two modules in this distribution. Date::Doomsday calculates
doomsday for a particular year. Date::DayOfWeek uses the doomsday
algorithm to calculate the day of the week for any given date.

Doomsday is a cute little idea invented by Dr John Conway that makes it
very easy to figure out the day of the week for any date.

For more information about the origins and mathematics surrounding
doomsday, see the following web sites:

http://rudy.ca/doomsday.html
http://quasar.as.utexas.edu/BillInfo/doomsday.html
http://www.cst.cmich.edu/users/graha1sw/Pub/Doomsday/Doomsday.html

WWW: https://metacpan.org/release/Date-DayOfWeek