“The Effect of Roflumilast on Absolute Neutrophil Count, MMP-9 Serum, % VEP1 Value, and CAT Scores in Stable COPD Patients”. Jurnal Respirologi Indonesia 42, no. 2 (April 18, 2022): 141–150. Accessed July 13, 2025. http://jurnalrespirologi.org/index.php/jri/article/view/265.