Grygonos,
Ok - for all intents and purposes, a reference is like a card from the card catalog in a library. The card tells you exactly where to go get the book you are looking for. You can de-reference (go get the book) anytime you like. This means you could pass the reference to the second sub or dereference back to the hash and pass that - it is completely up to you. If you pass a reference, the sub will need to know how to properly dereference it when it needs it.

Since it doesn't take very long to get used to using the proper syntax, I prefer passing by reference as a rule.

Cheers - L~R