M. Vargas V., “A contribution to the morphology of the eggs and nymphal stages of <i>Porocephalus stilesi</i> Sambon, 1910 and <i>Porocephalus clavatus</i> (Wyman, 1847) Sambon, 1910 (Pentastomida)”, Rev. Biol. Trop., vol. 17, no. 1, pp. 27–89, Jul. 1969.