Shelley, R. M.; Shear, W. A.; Leonard, W. P.; Ovaska, K. (2007). Diplopoda, Chordeumatida, Caseyidae, Opiona columbiana Chamberlin, 1951: distribution extensions into the Alexander Archipelago, Alaska, USA, Queen Charlotte Islands, British Columbia, Canada, and eastern & southern Washington State, USA. Check List, 3(1): 14-17
