References: & in front of functionnames

Hello. I've read a book, PHP DEVELOPER'S COOKBOOK, with great interest and it's a great contribution to my bookcollection :-) There is something I would like to know though....I have searched through all my books and sites on PHP, but didn't find the answer.... In chapter 16 (Creating a Database-Independent API with PHP) there are some functions written with a & in front of them. Ex. in DB/standard.php; function &db_fetchall($args=array()){ ... I've seen and used the pass by reference syntax on function parameters but not on functionnames. What effect does reference (&) have when used in front of the functionname?? It would help me a lot to get a fast answer. Kind regards Rolf Håkon Rensaa Norway