Artemisinin, Related Sesquiterpenes, and Essential Oil in Artemisia annua During a Vegetation Period in Vietnam - Woerdenbag, Herman J; Pras, Niesko; Chan, Nguyen Gia; Bang, Bui Thi; Bos, Rein; van Uden, Wim; Van Y, Pham; Van Boi, Nguyen; Batterman, Sieb; Lugt, Charles B (Planta Medica, 1994)