Lichong SHEN et al. 2020. Efficacy of Combination Therapy With Pirfenidone and Low-Dose Cyclophosphamide for Refractory Interstitial Lung Disease Associated With Connective Tissue Disease: A Case-Series of Seven Patients. Archives of Rheumatology. 35, 2 (Jun. 2020), 180–188. DOI:https://doi.org/10.46497/ArchRheumatol.2020.7381.