Marchand-Brynaert, J., Moya-Portuguez, M., Huber, I., & Ghosez, L. (1983). A Convenient Synthesis of Azetidine-2-thiones and Azetidin-2-imines. Chemical Society. Journal. Chemical Communications, 15, 818-819. https://doi.org/10.1039/c39830000818 (Original work published 1983)