here would be my main sources:
Just looked through my books, here is what i could come up with:
The reproductive husbandry of Pythons and boas by Ross
Reptiles, Jan. 96.
Reptiles, Feb. 96
Vivarium vol 6, issue no. 3
Living Snakes of the world by Mehrtens
Nonvenomous Snakes by Trutnau
Snakes by Harry Greene
Pythons and Boas by Stafford, sucky book, but a reference none the less
Search the web too, vpi, nerd, proexotics...there is also a paper floating out there by D. Barker and some other people detailing the differences between brong, curtus and breit.
15 pages would be tough, you'd be better off writing about pythons in general.