Krasimira Georgieva and Yordan Denev, Producing and Mechanical Testing of Urea-Formaldehyde Resin Foams Reinforced by Waste Phosphogypsum. journal = {International Journal of Materials and Metallurgical Engineering}, [online]. World Academy of Science, Engineering and Technology. July 2019, vol. 152(8). 408 - 414 [viewed 27 April 2024]. Available from: https://publications.waset.org/pdf/10010652.