I am trying to understand what that means
I know that declares a variable to an address of type node and that & gets the address of a variable. I also know that in a function parameter it is a call by reference pointer. But I have never seen it in a variable declaration before...
What does it mean exactly

```
Node *&ptr = root->mRight

```

I know about working with pointers and everything I am mostly asking about the Node \*& variable type. 
Thanks!