Discovery of the Apoptosis-Inducing Activity and High Accumulation of the Butenolides, Menisdaurilide and Aquilegiolide, in Dicentra spectabilis - McNulty, James; Poloczek, Joanna; Larichev, Vladimir; Werstiuk, Nick H; Griffin, Carly; Pandey, Siyaram (Planta Medica, 2007)