Dewar, MJ; Olivella, S; Stewart, JJ (1986). Mechanism of the Diels-Alder reaction: Reactions of butadiene with ethylene and cyanoethylenes. J. Am. Chem. Soc. 108 (19): 5771—9. doi:10.1021/ja00279a018. PMID22175326.
Danishefsky, S.; Kitahara, T. (1974). Useful diene for the Diels-Alder reaction. J. Am. Chem. Soc. 96 (25): 7807. doi:10.1021/ja00832a031.
Dewar, MJ; Olivella, S; Stewart, JJ (1986). Mechanism of the Diels-Alder reaction: Reactions of butadiene with ethylene and cyanoethylenes. J. Am. Chem. Soc. 108 (19): 5771—9. doi:10.1021/ja00279a018. PMID22175326.