CCalendar::GetWeekStart

static function GetWeekStart()
{
	if (!isset(self::$weekStart))
	{
		$days = array('1' => 'MO', '2' => 'TU', '3' => 'WE', '4' => 'TH', '5' => 'FR', '6' => 'SA', '0' => 'SU');
		self::$weekStart = $days[CSite::GetWeekStart()];

		if (!in_array(self::$weekStart, $days))
			self::$weekStart = 'MO';
	}

	return self::$weekStart;
}