1. Baylis , A. B. Hillman , M. E. D. Ger. Offen. 2,155,113 1972
2. Hillman , M. E. D. Baylis , A. B. U.S. Patent 3,743,669 1973
3. In the patents of ref. 1 only boiling points of the products were reported. Other examples in the patents deal with the extension of the reaction to other aldehydes and tertiary amine catalysts as well as to activated olefins such as α,β-unsaturated ketones, acrylamides, and nitroethylene
4. Culbertson , B. M. Post , L. K. U. S. Patent 4,279,833 1981