E. . G/Egziabher, J. . Hoyle, D. . Reddi, and T. . Belayneh, “Prevalence And Factors Associated With Postoperative Nausea And Vomiting at The University Of Gondar Teaching Hospital, Northwest Ethiopia, 2012: A Cross-Sectional Study”, Ethiop J Health Biomed Sci, vol. 6, no. 1, pp. 49–57, Sep. 2014.