Ramirez Caballero, Gustavo E., et al. “Effect of Impurities in the Crude Glycerol Polymerization Reaction to Produce Polyglycerol”. CT&F - Ciencia, Tecnología Y Futuro, vol. 9, no. 2, Nov. 2019, pp. 89-98, doi:10.29047/01225383.122.