Massazza, F., and M. T. Francardi. “Quick Determination of Free Lime: Modification of the Franke and Schlaepfer- Bukowski Methods”. Materiales de Construcción 21, no. 141 (March 31, 1971): 29–36. Accessed April 29, 2024. https://materconstrucc.revistas.csic.es/index.php/materconstrucc/article/view/1516.