1. Bentley, H.L., Herrlich, H., Lowen, R.: Improving constructions in topology. In: Herrlich, H., Porst, H.-E. (eds.) Category Theory at Work, pp. 3–20. Heldermann Verlag, Berlin (1991)
2. Bentley, H.L., Herrlich, H.: Doitchinov’s construct of supertopological spaces is topological. Serdica Math. J. 24(1), 21–24 (1998)
3. Bourbaki, N.: General Topology Part 1 (A translation of Éléments de Mathématique, Topologie Générale, originally published in French by Hermann, Paris), vol. 437. Addison-Wesley Pub., Boston (1966)
4. Castellini, G.: Categorical Closure Operators, vol. 300. Birkhäuser, Basel (2003)
5. Castellini, G.: Interior operators in a category: idempotency and heredity. Topol. Appl. 158, 2332–2339 (2011)