1. [B1] B. Banaschewski, Projective covers in categories of topological spaces and topological algebras. General Topology and Its Relations to Modern Analysis and Algebra, III (Proc. Conf. Kanpur, 1968), pp. 63–91. Academia, Prague, 1971.
2. [B2] N. Bourbaki, General Topology, Part 1, Addison-Wesley, Reading, Mass., 1966.
3. [B3] R. Brown, On sequentially proper maps and a sequential compactification, J. London Math. Soc. (2), 7 (1973), 515–522.
4. [BHR] H. L. Bentley, H. Herrlich, and W. A. Robertson, Convenient categories for topologists, preprint.
5. [BM] A. B⦊aszczyk and J. Mioduzewski, On factorization of maps through τX, Colloq. Math. 23 (1971), 45–52.