1. N. Bourbaki, Elements of mathematics: general topology, Palo Alto-London, 1966 (English translation of �l�ments de math�matique, topologie g�n�rale, Paris 1942)
2. D. van Dantzig, Zur topologischen Algebra III. Brouwersche und Cantorsche Gruppen. Compos. Math.3 (1936), 408?426
3. S. Grosser and M. Moskowitz, Compactness conditions in topological groups, J. Reine Angew. Math.246 (1971), 1?40
4. E. Hewitt, K.A. Ross, Abstract harmonic analysis, Berlin-G�ttingen-Heidelberg 1963
5. K.H. Hofmann, A. Mukherjea, Concentration functions and a class of non-compact groups. Math. Ann.256 (1981), 535?548