1. Špány, V.: Special surfaces and trajectories of the multidimensional state space. In: Proceedings of VŠT in Košice, Košice, no. 1, pp. 123–152 (1978). (in Slovak)
2. Špány, V., Pivka, L.: Boundary surfaces in sequential circuits. In: Beitrage zur Theoretischen Elektrotechnik, Das Internationale Symposium in Ilmenau, Ilmenau, pp. 90–99 (1988)
3. Špány, V., Pivka, L.: Dynamic properties of flip-flop sensors. J. Electr. Eng. 47(7–8), 169–178 (1996)
4. Špány, V., Galajda, P., Guzan, M.: Boundary surfaces of one-port memories. In: Tesla III Milenium: Proceedings of 5th International Conference, Beograd, pp. IV-131–137 (1996)
5. Guzan, M.: Limit cycles and trajectories in a multivalued memory cell. Acta Electrotechnica et Informatica 2(1), 36–41 (2002). (in Slovak)