“The Effect of Roflumilast on Absolute Neutrophil Count, MMP-9 Serum, % VEP1 Value, and CAT Scores in Stable COPD Patients”. Jurnal Respirologi Indonesia, vol. 42, no. 2, Apr. 2022, pp. 141-50, https://doi.org/10.36497/jri.v42i2.265.