1. M. F. Greaves, J. J. T. Owen andM. C. Raff,T and B Lymphocytes: Origin, Properties and Roles in Immune Responses (American Elsevier, New York 1974).
2. B. D. Janković inMacromolecules and Behavior (Ed.J. Gaito; Appleton-Century-Crofts, New York 1972), p. 99.
3. F. E. Bloom andR. Sidman, Neurosci. Res. Prog. Bull.11, 138 (1973).
4. E. G. Lapetina, E. F. Soto andE. De Robertis, Biochim. biophys. Acta135, 33 (1967).
5. B. D. Janković, J. Horvat, K. Mitrović andM. Mostarica, inSymposium on the Thymus (Tokai Univ., Tokyo 1975), in press.