Aull, C. E.: Some base axioms for topology involving enumerability.
(English).
In:
Franklin, S. P., Frolík, Z.
and Koutník, V. (eds.): General Topology and Its Relations to Modern Analysis and Algebra.
Proceedings of the Kanpur topological conference, 1968.
Academia Publishing House of the Czechoslovak Academy of Sciences, Praha, 1971.
pp. [55]-61