Green, Brian; Bentley, Michael D.; Chung, Bong Y.; Lynch, Nicholas G.; Jensen, Bruce L. (). „Isolation of Betulin and Rearrangement to Allobetulin. A Biomimetic Natural Product Synthesis”. Journal of Chemical Education (în engleză). 84 (12): 1985. Bibcode:2007JChEd..84.1985G. doi:10.1021/ed084p1985.
Green, Brian; Bentley, Michael D.; Chung, Bong Y.; Lynch, Nicholas G.; Jensen, Bruce L. (). „Isolation of Betulin and Rearrangement to Allobetulin. A Biomimetic Natural Product Synthesis”. Journal of Chemical Education (în engleză). 84 (12): 1985. Bibcode:2007JChEd..84.1985G. doi:10.1021/ed084p1985.