1. Rosenberg, E., Paulsen, C.A. (eds.): The human testis New York and London: Plenum 1970.
2. Johnson, A.D., Gomes, W.R., Vandemark, N.L. Vol. I, II, III. New York-London: Academic Press 1970–1971.
3. Voss, H.E., Oertel, G.W. (eds.): Androgene I. Handbook of experimental pharmacology, New Series, Vol. XXXV 3 xv/1. Berlin-Heidelberg-New York: Springer 1973.
4. Anberg, Ä.: The ultrastructure of the human spermatozoon. Acta obstet. gynec. scand. 36, Suppl. 2 (1957).
5. Burgos, M. H., Fawcett, D.W.: Studies on the fine structure of the mammalian testis. I. Differentation of the spermatids in the cat (Felis domestica). J. biophys. biochem. Cytol. 1, 287 (1955).