$this->this and avoiding circular references

Hi all- I've been trying to avoid circular references in some data import scripts and finally figured out how to do it. However, I wanted to ask you guys to make sure that what I'm doing is something that's legit and can be relied on into the future. Also, please note that I tried searching the archives for "this" and "this->this" but the searcher keeps removing "this" from my query! So sorry if this is asked and answered.... So, my objects are in a parent-child relationship and they both have links to each other... pretty standard circular reference scenario:

ParentObject: function addChildObject($c) {

    $this->children[] = $c;
    $c->setParent($this->this);		// this syntax is the only way I found to make "$this" not get refcounted here

} Now, to make this work as it should without incrementing the ref counts when storing the link to the parent, setParent() needs to have a non-refcounted pointer to the object: ChildObject: // need & in both places to make the ref not get ref-counted function setParent(&$parent) { $this->-parent = &$parent; }

My question is, is "$this->this" valid syntax? Can it be relied on? Is my overall approach sane? It's very important that I get memory management working in such a way here because the objects are used in large loops for importing data, and without this, the script uses unbounded amounts of memory. With this, it uses a finite amount of memory and works beautifully. Thanks in advance, Alan