[1]
E. Scott, J. D. Visser, C. A. Yetman, C. A. Yetman, L. Oliver, and D. G. Broadley, “Revalidation of Pyxicephalus angusticeps Parry, 1982 (Anura: Natatanura: Pyxicephalidae), a bullfrog endemic to the lowlands of eastern Africa”, Zootaxa, vol. 3599, no. 3, pp. 201–228, Jan. 2013.