Arbaningsih, S. R., Syarani, F., Ganie, R. A., & 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), 2123–2126. https://doi.org/10.3889/oamjms.2019.612