S. Jacobsen, H. Ko, E. Iversen, и C. Davis. Proceedings of the IEEE International Conference on Robotics and
Automation, стр. 1334--1339. Scottsdale, AZ, USA, (мая 1989)
1. Kim, 1. Kang, 1. Baik, и 1. Ko. snpd, (2007)Eighth ACIS International Conference on Software Engineering, Artificial Intelligence, Networking, and Parallel/Distributed Computing (SNPD 2007) pp. 556-561.