It looks like a doubly linked list actually is covered by that - a doubly linked list just happens to use opposite orderings on the two references. I'm going to

It looks like a doubly linked list actually is covered by that - a doubly linked list just happens to use opposite orderings on the two references. I'm going to go out on a limb and claim that we had doubly linked lists before 2006... or 2004 (is that the filing date?). Other prior art: about a gazillion structs with multiple list_head members in the Linux kernel. I'm guessing they don't have actual programmers review software patents?