Goldstein, S., Sory, D., Ghosez, L., Klessinger, M., & Friege, H. (1982). Allylic Substituent Effects On Reactivity of Double-bond. Societes Chimiques Belges. Bulletin, 91(5), 438. https://doi.org/10.1002/bscb.19820910597 (Original work published 1982)