"... a reference to the function ..."

Sorry for being horribly blunt stevieb, but that's just wrong!

Reference to the return value of this function (i.e. a scalarref):

$ perl -wE 'sub f { 42 } say \&f()'
SCALAR(0x7f8070805480)
[download]

Reference to a function (i.e. a coderef):

$ perl -wE 'sub f { 42 } say \&f'
CODE(0x7ff5d90314f0)
[download]

Another offering at the altar of "whomsoever personifies Confusion" :-) [reference taken from my reply to OP]