Santos Rodolfo Otávio, Laurin Michel, and Zaher Hussam. 2020. “A Review of the Fossil Record of Caecilians Gymnophiona (Tetrapoda; Lissamphibia; Gymnophionomorpha) With Comments on Its Use to Calibrate Molecular Timetrees” 131 (December). {Linnean Society of London}: 737–755. doi:10.1093/biolinnean/blaa148.
Scanferla Agustin, Zaher Hussam, Novas Fernando E., De Muizon Christian, and Cespedes Ricardo. 2013. “A New Snake Skull from the Paleocene of Bolivia Sheds Light on the Evolution of Macrostomatans”. PLoS One 8 (January): 1-9. doi:https://doi.org/10.1371/journal.pone.0057583.