1. P. J. Collins, Concordant mappings and the concordant-dissonant factorization of an arbitrary continuous function, Proc. Amer. Math. Soc. 27 (1971), 587–591.
2. J. M. Harvey, Topological functors from factorization (Proc. Int. Conf. Berlin 1978), Springer Lecture Notes in Math. 719 (1979) 102–111.
3. [He1] H. Herrlich, A generalization of perfect maps (Proc. Third Prague Topological Symposium. 1971), General Topology and Its Relations to Modern Analysis and Algebra III, Academia, Prague (1972) 187–191.
4. [He2] _____, Perfect subcategories and factorizations (Proc. Colloq. Karzthely, Topics in Topology). Colloq. Math. Soc. Janos Bolyai, 8, North Holland, Amsterdam (1974) 387–403.
5. [He3] _____, Topological functors, General Topology and Appl. 4 (1974) 125–142.