public static function findUniqueByZone( $name, $countryId, $provinceId, $zone ) {

		return self::find()->where( 'name=:name AND countryId=:cid AND provinceId=:pid AND zone=:zone', [ ':name' => $name, ':cid' => $countryId, ':pid' => $provinceId, ':zone' => $zone ] )->one();
	}