Grossman, R., Comesse, S., Rasne, R., Hattori, K., & Delong, M. (2003). Phosphoramidites are efficient, green organocatalysts for the Michael reaction. Mechanistic insights into the phosphorus-catalyzed Michael reaction of alkynones and implications for asymmetric catalysis. The Journal of Organic Chemistry, 68(3), 871-4. https://doi.org/10.1021/jo026425g (Original work published 2003)