1. G. Prota, Melanins and Melanogenesis, Academic Press, San Diego, CA, 1992.
2. G. Prota, M. d’Ischia, A. Napolitano, The chemistry of melanins and related metabolites, in: J.J. Nordlund, R.E. Boissy, V.J. Hearing, R.A. King, J.P. Ortonne (Eds.), The Pigmentary System: Its Physiology and Pathophysiology, Oxford University Press, New York, 1998, Chapt. 24, pp. 93–148.
3. L. Zeise, Analytical methods for characterization and identification of eumelanins, in: L. Zeise, M.R. Chedekel, T.B. Fitzpatrick (Eds.), Melanin: Its Role in Human Photoprotection, Valdenmar, Overland Park, KS, 1995, pp. 65–79.
4. The structure of melanins and melanogenesis-IV. On some natural melanins;Nicolaus;Tetrahedron,1964
5. Feomelanine e eumelanine da nuove fonti naturali;Fattorusso;Gazz. Chim. Ital.,1970