El-Wahab, Ashraf Hassan Fekry Abd, et al. “The Chemical Reactivity of Naphthols and Their Derivatives Toward α-Cyanocinnamonitriles and Ethyl α-Cyanocinnamates: A Review of Synthesis, Reactions and Applications of Naphthopyrano”. European Journal of Chemistry, vol. 4, no. 4, Dec. 2013, pp. 467-83, doi:10.5155/eurjchem.4.4.467-483.775.