T.  Rodriguez and Hermida, J., ?Key to the identification of the slugs (Gastropoda: Pulmonata) of Portugal?, Journal of Conchology, vol. 34, pp. 377-392, 1993.

T.  Rodriguez and Hermida, J., ?Key to the identification of the slugs (Gastropoda: Pulmonata) of Portugal?, Journal of Conchology, vol. 34, pp. 377-392, 1993.

A.  Sysoev and Schileyko, A., Land Snails and Slugs of Russia and Adjacent Countries. Sofia: Pensoft, 2009.