Arbaningsih, S. R., Syarani, F., Ganie, R. A. and Lelo, A. (2019) “The The Levels of Vitamin D, Metalloproteinase-9 and Tissue Inhibitor Metalloproteinase-1 in COPD Patients, Healthy Smokers and Non-Smokers of Indonesian Citizens”, Open Access Macedonian Journal of Medical Sciences, 7(13), pp. 2123–2126. doi: 10.3889/oamjms.2019.612.