I agree that this is an obvious invention. I think using the unqualified term "linked list" is misleading, though. As I pointed out elsewhere, references typically do not include the "multiply-linked list" when defining the linked list. They'll mention single, doubly, circularly, and possibly sorted linked lists. I don't see any mention of multiply-linked lists (or equivalent) in Intro to Algos or TaoCP. *

* It's possible that TaoCP covers them somewhere, but I don't see them in the early discussion of linked lists.