1. International Coffee Organization , 2017 , http://www.ico.org
2. Production, Composition, and Application of Coffee and Its Industrial Residues
3. R. C. Alves , F.Rodrigues , M. A.Nunes , A. F.Vinha and M. B. P. P.Oliveira , State of the art in coffee processing by-products , in Handbook of Coffee Processing By-Products , 2017 , ch. 1, pp. 1–26
4. J. León , Botánica de los cultivos tropicales , Editorial Agroamérica, Instituto Interamericano de Cooperación para la Agricultura , 2000
5. H.-D. Belitz , W.Grosch and P.Schieberle , Coffee, tea, cocoa , in Food Chemistry , ed. H.-D. Belitz , W. Grosch and P. Schieberle , Springer , Leipzig , 4th edn, 2009 , pp. 938–951