Gibbons, Khalil & Marinkelle 1997. Paraorientatractis semiannulata n. g., n. sp. (Cosmocercoidea: Atractidae) from the large intestine of the side-necked turtle, Podocnemis unifilis Troschel, 1848 (Testudines: Pelomedusidae) in Brazil. Memorias do Instituto Oswaldo Cruz, 92(3), May-Jun 1997: 359-364