Williams, T. (1981). "The niches of two sympatric softshell turtles, Trionyx muticus and Trionyx spiniferus, in Iowa". Journal of Herpetology. 15 (3): 303–308. doi:10.2307/1563433. JSTOR1563433.
jstor.org
Williams, T. (1981). "The niches of two sympatric softshell turtles, Trionyx muticus and Trionyx spiniferus, in Iowa". Journal of Herpetology. 15 (3): 303–308. doi:10.2307/1563433. JSTOR1563433.