1. Gorbman A, Bern HA: A textbook of comparative endocrinology. New York: Wiley, 1962.
2. Bargmann W: On the innervation of vertebrate endocrine organs. Int Congr Ser No 273 Endocrin, Proc Fourth Int Congr Endocrin Washington, 18–24 June 1972, pp 220–223.
3. Bargmann W: Über die Innervation der endokrinen Organe der Wirbeltiere. Nova Acta Leopoldina nr 217, Bd 41: 25–35. Halle: Deutsche Akademie d Naturforsch Leopoldina, 1975.
4. Scharrer B: General principles of neuroendocrine communication. The Neurosciences: Second Study Program. Schmitt FO (ed.). New York, The Rockefeller Univ Press, 1970, pp 519–529.
5. Scharrer B: Neuroendocrine Communication (neurohormonal, neurohumoral, and intermediate. Progr Brain Res Vol. 38. Ariens Kappers J. Schade JP (eds). Amsterdam, Elsevier, 1972, pp 7–18.