Stamboliyska, Bistra, Stefan Belishki, Nikifor Haralampiev, Denitsa Yancheva, Evelina Velcheva, Petya Penkova, Albena Lederer, and Dieter Fischer. “The Wall Paintings in the Russian Church St. Nicholas in Sofia: A Technological Study by Integrated Analytical Approach”. Proceedings of the Bulgarian Academy of Sciences 76, no. 3 (March 27, 2023): 377–387. Accessed November 29, 2023. https://proceedings.bas.bg/index.php/cr/article/view/271.