1. KYUNG J. CHO, BRUSE D. DOREST, J. Nucl. Med., 15 (1974) 1171.
2. M.A. WINSTON, P. GUTH, J.S. ENDOW, W.H. BLAHD, J. Nucl. Med., 15 (1974) 662.
3. A.G. MATTAR, Y. LAOR, J. Nucl. Med., 15 (1974) 707.
4. P.PH.L. OTTO, Dutch Patent, Appl. No. 69.08609.
5. J.P. GREENSTEIN, M. WINITZ, Chemistry of the Amino Acids, Wiley, New York, 1961, p. 715.