Yoseff BJ, Guerrero J, López Valadéz F. Intromisión of a stimulus in a fixed-interval 60-sec schedule, varying the duration of the stimulus. MJBA [Internet]. 2011 Jan. 27 [cited 2024 May 24];6(2):157-66. Available from: https://revistas.unam.mx/index.php/rmac/article/view/23692