protected function getReferences(array $row){
		$references = [];
		$types      = [];

		foreach($row as &$field){
			$type = gettype($field);

			if($type === 'integer'){
				$types[] = 'i';
			}
			elseif($type === 'double'){
				$types[] = 'd';
			}
			else{
				$types[] = 's';
			}

			$references[] = &$field;
		}

		array_unshift($references, implode('', $types));

		return $references;
	}