Valverde, J. L., J. Lobato, I. Fernández, L. Marijuán, S. Pérez-Mohedano, and R. Talero. 2005. “Ferrous Sulphate Mono and Heptahydrate Reduction of Hexavalent Chromium in Cement: Effectiveness and Storability”. Materiales De Construcción 55 (279):39-52. https://doi.org/10.3989/mc.2005.v55.i279.197.