<html>
<body>
class MyClass {
public $amount;
}
// Create an object with a reference
$value = 5;
$obj = new MyClass();
$obj->amount = &$value;
// Clone the object
$copy = clone $obj;
// Change the value in the original object
$obj->amount = 6;
// The copy is changed
print_r($copy);
</body>
</html>
MyClass Object ( [amount] => 6 )