Richard J. Butler, Stephen L. Brusatte, Brian B. Andres and Roger B. J. Benson (2012). «How do geological sampling biases affect studies of morphological evolution in deep time? A case study of the Pterosauria (Reptilia: Archosauria)». Evolution66 (1): 147-162. doi:10.1111/j.1558-5646.2011.01415.x.