Malewska, E., M. Trzyna, A. Sabanowska, A. Prociak, and P. Koniorczyk. “The Influence of Expandable Polystyrene Fillers on Properties of Water-Blown Rigid Polyurethane Foams”. Polimery, vol. 56, no. 11-12, Dec. 2011, pp. 865-8, https://ichp.vot.pl/index.php/p/article/view/979.