Rössner, E.; Schönfeld, J.; Ahrens, D. Onthophagus (Palaeonthophagus) medius (Kugelann, 1792)—a Good Western Palaearctic Species in the Onthophagus Vacca Complex (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini). Zootaxa 2010, 2629, 1–28.