D. Floreano, S. Nolfi, and F. Mondada. From Animals to Animats 5: Proceedings of the Fifth International Conference on Simulation of Adaptive Behavior, (1998)
M. Gienger, K. Loffler, and F. Pfeiffer. Proceedings of the 2nd International Conference on Climbing and Walking Robots (CLAWAR), page 49--58. Portsmouth, UK, (1999)