Stoll, U.W., and E.R. Streed. 1954. “Use of a Flame Photometer for Estimating the Cement Contenta of Soil-Cement and Pozzolan-Cement Mixtures”. Materiales De Construcción 4 (047):3-3. https://doi.org/10.3989/mc.1954.v04.i047.2541.