1. Geissman T A and Crout D H G 1969 Organic chemistry of secondary plant metabolites (California: Freeman, Cooper and Company) pp. 183–230
2. Murray M T 1996 Encyclopedia of nutritional supplements (California: Prima Publishing) pp. 320–331
3. Proestos C, Boziaris I S and Nychas J E 2005 Food Chem. 93 1998
4. Yenjai C, Prasanphen K, Daodee S and Kittakoop P 2004 Fitoterapia 75 89
5. Furuta T, Kimura T, Kondo S, Wakimoto T, Nukaya H, Tsuji K and Tanaka K 2004 Tetrahedron 60 9375