Markova, Kremena Tsankova, et al. “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.