https://reptilesmagazine.com/breeding-the-rubber-boa/

https://login.jpllnet.sfsu.edu/login?qurl=https://www.jstor.org/stable/1565355 (SIZE, SEXUAL DIAMORPHISM, REPRODUCTION)

https://login.jpllnet.sfsu.edu/login?qurl=https://www.jstor.org/stable/41710750 (NOTES ON CHARINA BOTTAE IN UTAH: REPRODUCTION)

https://www.snakesforpets.com/what-are-spurs-on-snakes/ (cloaca spurs)

https://www.snakesforpets.com/how-snakes-reproduce/ (General snake mating)

Hall, Brian. (2003). Descent with modification: The unity underlying homology and homoplasy as seen through an analysis of development and evolution. Biological reviews of the Cambridge Philosophical Society. 78. 409-33. 10.1017/S1464793102006097. (python spur image)