2R,3R-(+)-3-Acetoxy-4′,5-dihydroxy-7-methoxyflavanone and 2R,3R-(+)-3-acetoxy-4′,5,7-trihydroxyflavanone: Two new 3-acetylated dihydroflavonols from Aframomum pruinosum Gagnepain (Zingiberaceae) - Ayafor,J.F.; Connoly,J.D. (Journal of the Chemical Society. Perkin Transactions, 1981)