You can declare a reference to a function, just like you can declare a pointer to a function. For example:
void f(int n)
void (&rf) (int) = f; //bind rf as a reference to f()
rf(5); //call f() through its reference
The major difference between a pointer and a reference to a function is that the latter must always be bound to an existing function (i.e., it may not be null or dangling), and you cannot re-bind another function to it once you have initialized it.