[math-fun] Original source of "XOR doubly linked list" hack?

Wikipedia is sometimes pretty lame. Their references about the (in)famous "XOR doubly linked list" hack miss the origin by perhaps 40 years. Does anyone here know who originally came up with this hack and if so, where it was first published? I seem to recall hearing about it while an undergraduate at MIT in the late '60's, but it may have become folklore by then.