Frenking, G., Köhler, K. F., & Reetz, M. T. (1991). On the origin of π-facial diastereoselectivity
in nucleophilic additions to chiral carbonyl compounds. 2. Calculated transition state structures for the addition of nucleophiles
to propionaldehyde 1, chloroacetyldehyde 2, and 2-chloropropionaldehyde 3. Tetrahedron,
47(43), 9005-9018. doi:10.1016/S0040-4020(01)86505-4.