Shuifang, Xu, Zhang Fengying, He Yuhua, Lv Xiyun, Tian Jinfang, Qi YI, and Xu Fengying. 2020. “Evaluation of the Comparative Influence of Magnesium Sulfate Single and Combination With Ritodrine Hydrochloride in the Prevention of Preterm Delivery”. Bioscience Journal 36 (4). Uberlândia, MG:1491-97. https://doi.org/10.14393/BJ-v36n4a2020-49897.