Markova, K., T. Dovramadjiev, and G. Jecheva. “Methodology for Creating 3D Paper Unfolded Models With Complex Geometry Using Open-Source Software and Resources With Free Personal and Commercial License”. ANNUAL JOURNAL OF TECHNICAL UNIVERSITY OF VARNA, BULGARIA, Vol. 2, no. 1, June 2018, pp. 39 -46, doi:10.29114/ajtuv.vol2.iss1.67. Accessed 18 Aug. 2025.