GORAYEB, R.; TODOROV, J. C. Key-pecking maintained by negative reinforcement: Multiple schedules. Mexican Journal of Behavior Analysis, [S. l.], v. 3, n. 2, p. 161–168, 2011. DOI: 10.5514/rmac.v3.i2.23642. Disponível em: https://journals.unam.mx/index.php/rmac/article/view/23642. Acesso em: 27 jul. 2024.