Varbanova-Dencheva, Kristina, and Radostina Todorova. “National Infrastructure for University Repositories Possible Model”. Digital Presentation and Preservation of Cultural and Scientific Heritage 4 (September 30, 2014): 218–223. Accessed April 30, 2024. https://dipp.math.bas.bg/dipp/article/view/dipp.2014.4.26.