public static function roundTimestampToWeek($timestamp)
    {        
        $roundedToDay = self::roundTimestampToDay($timestamp);
        $weekDay  = date('w', $roundedToDay); # 1 = Monday
        $daysToSubtract = $weekDay - 1;
        $roundedToWeek = strtotime("-" . $daysToSubtract . " day", $roundedToDay);
        
        return $roundedToWeek;
    }