Aspe, N. M., and S. W. James. “New Species of Pheretima (Oligochaeta: Megascolecidae) from the Mt. Malindang Range, Mindanao Island, Philippines”. Zootaxa, vol. 3881, no. 5, Nov. 2014, pp. 401–439, doi:10.11646/zootaxa.3881.5.1.