Selim G. Akl, Cristian S. Calude, Michael J. Dinneen, Grzegorz Rozenberg, Todd Wareham: Unconventional Computation, 6th International Conference, UC 2007, Kingston, Canada, August 13-17, 2007, Proceedings. Lecture Notes in Computer Science 4618, Springer 2007, ISBN 978-3-540-73553-3