Cintra, Priscila Pavini, et al. “Cardiorespiratory and Electrocardiographic Effects of Methadone or Morphine in the Perioperative Period in Anesthetized Dogs With Continuous Rate Infusion of Propofol and Submitted to Ovariohysterectomy”. Semina: Ciências Agrárias, vol. 38, no. 1, Mar. 2017, pp. 209-20, doi:10.5433/1679-0359.2017v38n1p209.