[1] S. Burris: Representation theorems for closure spaces. Colloq. Math. 19 (1968), 2, 187-193. MR 0227074 | Zbl 0179.03502

[2] S. Burris: Closure homomorphisms. Journal of Algebra 15 (1970), 68-71. MR 0253961 | Zbl 0194.01402

[3] S. Burris: Embedding algebraic closure spaces in 2-ary closure spaces. Portugal. Math. 31 (1972), 4, 183-185. MR 0306079 | Zbl 0238.08005

[4] E. Čech: Topological spaces. Academia Prague 1966. MR 0211373

[5] J. Chvalina: Uzávěrove operace na iteračních systémech. Knižnice odb. a věd. spisů VUT v Brně, svazek B-56 (1975), 137-143. MR 0412076

[6] O. Kopeček M. Novotný: On some invariants of unary algebras. Czech. Math. Journal 24 (99), (1974), 219-246. MR 0347703

[7] M. Novotný: Sur un problème de la théorie des applications. Publ. Fac. Sci. Univ. Masaryk, 344 (1953), 53-64. MR 0061149

[8] M. Novotný: Über Abbildungen von Mengen. Pacific Journ. Math. 13 (1963), 1359-1369. MR 0157143

[9] W. Stucky H. Walter: Minimal linear realizations of autonomous automata. Information and Control 16 (1970), 66-84. MR 0282758