Journal Article
Kraker, D.; Franssen, M. C. R.; Joerink, M.; De Groot, A.; Bouwmeester, H. J.: Biosynthesis of costunolide, dihydrocostunolide, and leucodin. Demonstration of cytochrome P450-catalyzed formation of the lactone ring present in sesquiterpene lactones of chicory. Plant Physiology
129 (1), pp. 257 - 268 (2002)