For more information about the other types of references (e.g. coderef, arrayref etc), see this question: <a href="http://stackoverflow.com/questions/1399833/how-can-i-get-perls-ref-function-to-return-ref-io-and-lvalue">http://stackoverflow.com/questions/1399833/how-can-i-get-perls-ref-function-to-return-ref-io-and-lvalue</a> and perldoc perlref.