(Rel)-1β,2α-di-(2,4-dihydroxy-6-methoxybenzoyl)-3β,4α-di-(4-methoxyphenyl)-cyclobutane and other flavonoids from the aerial parts of Goniothalamus gardneri and Goniothalamus thwaitesii. - Seidel,V.; Bailleul,F.; Waterman,P.G. (Phytochemistry, 2000)