Gosik, R., and P. Sprick. “Morphology and Identification of the Pupae of Seven Species of the Genus Otiorhynchus Germar, 1822 (Coleoptera, Curculionidae, Otiorhynchini)”. Zootaxa, vol. 3483, no. 1, Sept. 2012, pp. 39–57, doi:10.11646/zootaxa.3483.1.3.