Synergistic Induction of 1,25-Dihydroxyvitamin D3- and All-trans-Retinoic Acid-Induced Differentiation of HL-60 Leukemia Cells by Yomogin, a Sesquiterpene Lactone from Artemisia princeps - Kim, Seung Hyun; Kim, Tae Sung (Planta Medica, 2002)