Efficacy and safety of leflunomide and cyclophosphamide in  sequential therapy of systemic lupus erythematosus
Ning Xiaoran， Zhang Fengxiao， Li Fang， Sun Lijun， Zheng Guimin
Clinical Focus . 2017, (10): 865 -868 .  DOI: 10.3969/j.issn.1004-583X.2017.10.010