Tuluce, D., E. Kaplan Serin, and S. Kutluturkan. “Oral Mucous Membrane Condition of the Patients With Chronic Obstructive Pulmonary Disease and the Measures Taken for the Protection”. Annals of Medical Research, vol. 27, no. 11, May 2021, pp. 2994-9, http://annalsmedres.org/index.php/aomr/article/view/1038.