Sousa-Pinto, B., and L. F. Azevedo. “Critical Appraisal of a Systematic Review and Meta-Analysis: Performing Meta-Analysis and Addressing Heterogeneity”. Journal of the Portuguese Society of Anesthesiology, vol. 28, no. 3, Sept. 2019, pp. 187-91, doi:10.25751/rspa.18503.