1. Bourjij, A. and Koenig, D. (1998). An original petri net state estimation by a reduced luenberger observer. In In Proceedings of American Control Conference. San Diego.
2. Cardoso, J., Valette, R., and Dubois, D. (1989). Petri nets with uncertain markings. In 10th international conference on application and Theory of Petri nets. Bonn, Germany.
3. Giua, A. (1997). Petri net state estimators based on event observation. In In Proceedings of 1997 IEEE Conference on Decision and Contr ol, San Diego.
4. Holloway, L. E. and Ashley, J. Jr. (1998). Condition languages and condition systems for modeling ambiguous control specifications. In IEE International Workshop on Discrete Event Systems (WODES98), Cagliari.
5. Holloway, L. E. and Guan, X. (1999). Assembling taskblocks for control of discrete event system. In IEEE Conference on Decision and Control. Phoenix.