Frederiksen, S. B., and H. Enghoff. “East African Odontopygid Millipedes 1: Five New Species of Xystopyge (Attems, 1909) and a Proposal for a New Gonopod Terminology (Diplopoda; Spirostreptida; Odontopygidae)”. Zootaxa, vol. 3485, no. 1, Sept. 2012, pp. 69–82, doi:10.11646/zootaxa.3485.1.5.