Doitchinov, D.: The notion of $\cal K$-shape.
(English).
In:
Novák, Josef (ed.): General topology and its relations to modern analysis and algebra IV, Proceedings of the fourth Prague topological symposium, 1976.
Part B: Contributed Papers.
Society of Czechoslovak Mathematicians and Physicist, Praha, 1977.
pp. 95-98
