Choque-Quispe, D.; Ligarda-Samanez, C.; Ramos-Pacheco, B.; Solano-Reynoso, A.; Quispe-Quispe, Y. Caffeine and UV-Vis Scanning and the Water Quality Index in the High-Andean Watershed of the Chumbao River, Andahuaylas, Apurímac, Perú. TQ 2019, 39, 604-620.