@article{Gavrilov_1978, title={Certain operations with the sets of discrete states}, volume={4}, url={https://cyber.bibl.u-szeged.hu/index.php/actcybern/article/view/3163}, number={1}, journal={Acta Cybernetica}, author={Gavrilov, M. A.}, year={1978}, month={Jan.}, pages={25-35} }