Lekskulchai, V. “Urinary nicotine and cotinine concentrations in hand-rolled cigarette smokers, filter cigarette smokers, and passive smokers exposed to ETS”. Thai Journal of Toxicology, vol. 25, no. 2, June 2020, p. 60, https://li01.tci-thaijo.org/index.php/ThaiJToxicol/article/view/243923.