1. P. Antoine, Étude élémentaire des categories d'ensembles structures. Bull. Soc. Math. Belgigue18, 142?164(1966).
2. D.Boyer and A.Mader, Functorial topologies on abelian groups. Preprint.
3. B.Charles, Méthodes topologiques en Théorie des groupes abéliens. Proc. Colloq. Abelian Groups, Budapest 1964.
4. T. H.Fay, E. P.Oxford and G. L.Walls, Preradicals in abelian groups. Houston J. Math. To appear;
5. L.Fuchs, Infinite Abelian Groups. New York-London Vol. I. 1970.