Salas, A., J. Torres, R. Mejía de Gutiérrez, and S. Delvasto. “Engineering Properties of Blended Concrete With Colombian Rice Husk Ash and Metakaolin”. Ingeniería Y Competitividad, vol. 15, no. 2, Dec. 2013, doi:10.25100/iyc.v15i2.2609.