KOVACHEVA, S.; DIMITROVA, L.; PEZHGORSKI, K. E-learning environment UNESCO Bulgarian Architectural Heritage Sites. Digital Presentation and Preservation of Cultural and Scientific Heritage, [S. l.], v. 6, p. 191–198, 2016. DOI: 10.55630/dipp.2016.6.18. Disponível em: https://dipp.math.bas.bg/dipp/article/view/dipp.2016.6.18. Acesso em: 5 may. 2024.