Fonksiyon isminden önce & ne anlama geliyor?

Does that mean that the $result is returned by reference rather than by value? If yes then is it correct? As I remember you cannot return a reference to a local variable as it vanishes once the function exits.

function &query($sql) {
 // ...
 $result = mysql_query($sql);
 return $result;
}

Ayrıca, nereye böyle bir sözdizimi alışmak yok practice?