1. Jongmans, F., andC. Heuchenne: Localisation des attributs topologiques. Bull. Soc. Royale Sci. Liège31, 22?50 (1962).
2. Melley, J. L.: General topology. New York: D. Van Nostrand Co., Inc. 1955
3. McAllister, B. L.: Cyclic elements in topology ? a history. Amer. Math. Monthly73, 337?350 (1966).
4. McAuley, L. F.: Local cyclic connectedness. I. Cyclic subelements of cyclic elements. Notices Amer. Math. Soc.5, 698 (1958) (abstract.).
5. Wallace, A. D.: The acyclic elements of a Peano space. Bull. Amer. Math. Soc.47, 778?780 (1941).