Kovacheva, Stefka, and Ludmila Dimitrova. “An E-Learning Environment – a Tool for Presentation of Knowledge about Bulgarian Cultural Heritage Sites”. Digital Presentation and Preservation of Cultural and Scientific Heritage 7 (September 10, 2017): 169–180. Accessed December 26, 2024. https://dipp.math.bas.bg/dipp/article/view/dipp.2017.7.15.