Identification of Intermediates and Enzymes Involved in the Early Steps of Artemisinin Biosynthesis in Artemisia annua - Bertea, C M; Freije, J R; van der Woude, H; Verstappen, F W A; Perk, L; Marquez, V; De Kraker, J-W; Posthumus, M A; Jansen, B J M; de Groot, Ae; Franssen, M C R; Bouwmeester, H J (Planta Medica, 2005)