Lesigyarski, Deyan, Iskra Tsvetanska, and Inna Dimitrova. “Raman Spectroscopy of Medieval Manuscripts in Bulgarian National Library – Preliminary Results”. Digital Presentation and Preservation of Cultural and Scientific Heritage 15 (September 5, 2025): 129–136. Accessed September 10, 2025. https://dipp.math.bas.bg/dipp/article/view/dipp.2025.15.12.