by Al-Mulhem, M., Al-Maghrabi, T.
Published in IEEE transactions on systems, man and cybernetics. Part B, Cybernetics (01.08.1998)

by Ullman, Jeffrey D., Yannakakis, Mihalis
Published in SIAM journal on computing (01.02.1991)

by Al-Mulhem, M., Al-Maghrabi, T.
Published in CCECE '97. Canadian Conference on Electrical and Computer Engineering. Engineering Innovation: Voyage of Discovery. Conference Proceedings (1997)