Olejnik, Tomasz P., and Elżbieta Sobiecka. “Utilitarian Technological Solutions to Reduce CO2 Emission in the Aspect of Sustainable Development”. Problemy Ekorozwoju, vol. 12, no. 2, July 2017, pp. 173-9, https://ph.pollub.pl/index.php/preko/article/view/4990.