sub getWeekStart {
	#----------------------------------------------------------
	# Return the date of the Monday which starts a given week
	# Required parameters: year (4 digit) and week
	#
	# Uses ISO8601 definition of week numbers
	#
	# ADSB 21 November 1998
	#----------------------------------------------------------

	local (@tm,$time,$year,$week,$wday);
	use POSIX;

	($year,$week)=@_;

	# With ISO8601 week numbers, 4 January is always in week 01
	@tm=(0,0,12,4,0,$year-1900,0,0);

	# Increment the day of the month by 7 times the weeks to add
	$tm[3] += (($week-1)*7);

	# Get the number of seconds since the epoch
	$time=mktime(@tm);

	# Fill in the struct tm again (because Perl's mktime() doesn't)
	@tm=localtime($time);

	# Find out which day of the week it is
	$wday=$tm[6];

	# Move Sunday to the end of the week
	if ($wday == 0) { $wday = 7;}

	# Wind day of week back to Monday
	$tm[3] -= ($wday-1);

	$time=mktime(@tm);
}

1;