Sahin Yuksek, M., A. Onur, and S. Uslu. “PO2 and ETCO2 Changes in Chronic Smokers During Anaesthesia and in the Recovery Room”. Annals of Medical Research, vol. 4, no. 4, May 2021, pp. 0413-7, http://www.annalsmedres.org/index.php/aomr/article/view/2640.