Intuvanich, S.- thitaya, C. Angkurawaranon, and K. Pinyopornpanish. “Hospitalization of patients with acute exacerbation of chronic obstructive pulmonary diseases in Sarapee Hospital: A retrospective study of prevalence and associated factors”. Biomedical Sciences and Clinical Medicine, vol. 57, no. 3, July 2018, pp. 151-7, https://he01.tci-thaijo.org/index.php/CMMJ-MedCMJ/article/view/93587.