[Phpgroupware-developers] improved version of holidays for .NL

[stacker]

One fixed date national holiday was missing, being the 5th of May, known as 
liberation day.

Is there a way to calculate easter, and other more or less christian holidays?
the ones that are dates of importance are: good friday, easter, easter 
monday, Ascension day, whit sunday, whit monday.
These somehow get calculated with respect to Easter, with Whit Sunday being 
the 7th sunday after easter, and ascension day being the thursday before 
the 6th sunday after easter, (good friday being the friday before easter).
I have not been able to quickly descern how easter is calculated.

Regards,

Huub
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NL nieuwjaarsdag 1 1 0 0 0 NL koninginnedag 30 4 0 0 0 NL bevrijdingsdag 5 
5 0 0 0 NL 1e kerstdag 25 12 1 0 0 NL 2e kerstdag 26 12 0 0 0