PHP references allow you to make two variables to refer to the same content. Meaning, when you do:
Note: $a and $b are completely equal here, that's not $a is pointing to $b or vice versa, that's $a and $b pointing to the same place.
The second thing references do is to pass variables by-reference. This is done by making local function variable and caller variable to be reference to the same content. Example:
The third thing reference can do is return by-reference.