Markova, K. T., Dovramadjiev, T. A., & Jecheva, G. V. (2018). 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, 2(1), 39–46. https://doi.org/10.29114/ajtuv.vol2.iss1.67