Justs, Janis, Genadij Shakhmenko, Diana Bajare, and Nikolajs Toropovs. 2015. “Comparison of Pozzolanic Additives for Normal and High Strength Concrete”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 2 (August): 79-84. https://doi.org/10.17770/etr2011vol2.979.