Erich Grädel, Lukasz Kaiser, Roman Rabinovich. Directed Graphs of Entanglement Two. In Miroslaw Kutylowski, Witold Charatonik, Maciej Gebala, editors, Fundamentals of Computation Theory, 17th International Symposium, FCT 2009, Wroclaw, Poland, September 2-4, 2009. Proceedings. Volume 5699 of Lecture Notes in Computer Science, pages 169-180, Springer, 2009. [doi]
Abstract is missing.