1. Accordi F, Grassi Milano E (1977) Catecholamine-secreting cells in the adrenal gland of Bufo bufo during metamorphosis and in the adult. Gen Comp Endocrinol 33:187–195
2. Accordi F, Grassi Milano E (1990) Evolution and development of the adrenal gland in amphibians. Fortschr Zool 38:257–268
3. Accordi F, Mastrolia L, Grassi Milano E, Manelli H (1975) Electron microscopic observations of adrenal chromaffin cells in the frog Rana esculenta during embryonal development and metamorphosis. Riv Biol 68:135–163
4. Balment RJ, Henderson IW, Chester Jones I (1980) The adrenal cortex and its homologues in vertebrates; evolutionary considerations. In: General Comparative and Clinical Endocrinology of the Adrenal Cortex. Chester Jones I, Henderson IW (eds). Academic Press, London, vol 3, pp 525–562
5. Butler DG (1973) Structure and function of the adrenal gland of fishes. Am Zool 13:839–879