Panicker, Chacko Yohannan, et al. “FT-IR, FT-Raman and Ab-Initio Studies of 1,3-Diphenyl Thiourea”. European Journal of Chemistry, vol. 1, no. 3, Sept. 2010, pp. 173-8, doi:10.5155/eurjchem.1.3.173-178.42.