QU, J.; YANG, J.; CHEN, M.; CUI, L.; WANG, T.; GAO, W.; TIAN, J.; WEI, R. MicroRNA-21 as a diagnostic marker for hepatocellular carcinoma: A systematic review and meta-analysis: MiR-21 in HCC. Pakistan Journal of Medical Sciences, v. 35, n. 5, 22 Aug. 2019.