New cardinal invariants for topological spaces.
(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. [201]-206