The "Cliff Notes" version of your question is a reference is a pointer but with less versatility. The reference is simpler and easier to use. A reference variable cannot be altered to refer to any variable except the one to which it was initialized.
A reference passed to another function is preferred if possible because while the receiving function has a copy of the value in the address passed, it cannot change the value in the original function. Thus protecting the original value.
References cannot be used for array notation.
