Cristobal Coaguila Berly David, and Barriga Paria Christ Jesus. 2021. “Optimization of the Health and Safety Protocol for Covid-19 through the Use of the QR Code in the Tailing Disposal System Project, Quellaveco - Moquegua, 2020”. International Journal of Engineering and Management Research 11 (5):129-42. https://doi.org/10.31033/ijemr.11.5.16.