“Intra- and Extra-Individual Biological Variability of Total Calcium, Urea, and Creatinine in Pre-Dialysis and Post-Dialysis Adult Patients With Chronic Renal Failure”. Revista De La Sociedad Ecuatoriana De Nefrología, Diálisis Y Trasplante, vol. 10, no. 1, Feb. 2022, pp. 13-20, https://doi.org/10.56867/8.