@article{Gergely_Németi_1975, title={Logical foundations for a general theory of systems}, volume={2}, url={https://cyber.bibl.u-szeged.hu/index.php/actcybern/article/view/3120}, number={3}, journal={Acta Cybernetica}, author={Gergely, Tamás and Németi, István}, year={1975}, month={Jan.}, pages={261-276} }