The following publications are possibly variants of this publication:
- Minimum matrix representation of closure operationsJános Demetrovics, Zoltán Füredi, Gyula O. H. Katona. DAM, 11(2):115-128, 1985. [doi]
- On the Number of Databases and Closure OperationsG. Burosch, János Demetrovics, Gyula O. H. Katona, Daniel J. Kleitman, Alexander A. Sapozhenko. TCS, 78(2):377-381, 1991.