Martins, António M. De Frias, Carlos P. Brito, and Thierry Backeljau. 2013. “Oxychilus (Drouetia) viridescens (Gastropoda: Pulmonata: Oxychilidae), a New Species from Santa Maria, Açores, and a Review of the Subgenus”. Zootaxa 3619 (3). Auckland, New Zealand:343–368. https://doi.org/10.11646/zootaxa.3619.3.5.