Doğanay, G., Ekmekçi, P., Kazbek, B. K., Yılmaz, H., Erkan, G., & Tüzüner, F. (2017). Effects of alfentanil or fentanyl added to propofol for sedation in colonoscopy on cognitive functions: Randomized controlled trial. Turkish Journal of Gastroenterology, 28(6), 453–459. https://doi.org/10.5152/tjg.2017.16489