Bogdanova, Galina, Kilian Stoffel, Todor Todorov, and Nikolay Noev. “Building OWL Ontology of Unique Bulgarian Bells Using Protégé Platform”. Digital Presentation and Preservation of Cultural and Scientific Heritage 2 (September 30, 2012): 161–166. Accessed May 6, 2024. https://dipp.math.bas.bg/dipp/article/view/dipp.2012.2.8.