Edouard Bonnet, Florian Jamain, Abdallah Saffidine. Havannah and TwixT are PSPACE-complete. In H. Jaap van den Herik, Hiroyuki Iida, Aske Plaat, editors, Computers and Games - 8th International Conference, CG 2013, Yokohama, Japan, August 13-15, 2013, Revised Selected Papers. Volume 8427 of Lecture Notes in Computer Science, pages 175-186, Springer, 2013. [doi]
Abstract is missing.