**By knowing the date, calculate the day number in a certain year and the week number in the year:**

M.Y.: if the week number "0" appears, it means that it's the last week of the previous year or the first week of the following year.

**By knowing the day number in the year, find the date:**

The functions to calculate the day number in a certain year were got from: Meeus Jean, Astronomia con il computer, Hoepli, Milano, 1990.

The calendar | Versione italiana |

Author: Eugenio Songia

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Creation date: 26/5/2007. Last update: 1/5/2016