Ivanova B. Natalia and Djambova ΠΆ. Svetlana and Hristev S. Ivailo, Investigation of the Acoustic Properties of Recycled Felt Panels and Their Application in Classrooms and Multi-Purpose Halls. journal = {International Journal of Civil and Environmental Engineering}, [online]. World Academy of Science, Engineering and Technology. April 2024, vol. 208(4). 184 - 187 [viewed 17 May 2024]. Available from: https://publications.waset.org/pdf/10013617.