Cyruliński, Zdzisław, Sławomir Drewnowski, and Wojciech Marks. 2006. “The Prestressed-Expanded Beams Made of Glued Wood”. Roads and Bridges – Drogi I Mosty 5 (3):5-16. https://www.rabdim.pl/index.php/rb/article/view/v5n3p5.