Affanni, J. M.; Cervino, C. O.; Marcos, H. J. A. (2001). «Absence of penile erections during paradoxical sleep. Peculiar penile events during wakefulness and slow wave sleep in the armadillo». Journal of Sleep Research. 10 (3): 219–228. PMID11696075. doi:10.1046/j.1365-2869.2001.00259.x
Affanni, J. M.; Cervino, C. O.; Marcos, H. J. A. (2001). «Absence of penile erections during paradoxical sleep. Peculiar penile events during wakefulness and slow wave sleep in the armadillo». Journal of Sleep Research. 10 (3): 219–228. PMID11696075. doi:10.1046/j.1365-2869.2001.00259.x