Evaluation of estrogenic activity of plant extracts for the potential treatment of menopausal symptoms - Liu, J; Burdette, J E; Xu, H; Gu, C; van Breemen, R B; Bhat, K PL; Booth, N; Constantinou, A I; Pezzuto, J M; Fong, H HS; Farnsworth, N R; Bolton, J L (J Agric Food Chem, 2001)