> > ISO-week: week that has more than 4 day and start in Sunday.
> What about weeks that start in Monday (as here in Norway)?
You can probably calculate that from the existing date/time code. But it
isn't ISO-8601. Karel was referring to the ISO-defined week for which
the first week of the year is that week which contains a Thursday. It
has the rather strange outcome that for some years, days in the previous
or subsequent calendar year fall into the adjacent "ISO-year".
- Thomas