Genchev, Yancho, Teodor Lulchev, and Desislava Hristodorova. “INFLUENCE OF THE TYPE OF UPHOLSTERY MATERIALS ON THE SOFTNESS OF UPHOLSTERY WITH INNER SPRING UNITS”. Innovation in Woodworking Industry and Engineering design 5, no. 1 (May 19, 2016). Accessed April 14, 2026. http://innojs.ltu.bg/index.php/scjournal-inno/article/view/203.