Georgieva Trifonova, Tsvetanka, and Kaloyan Zdravkov. “Digital Library of Scientific Forums Organized by the Faculty of Mathematics and Informatics of the University ‘St. Cyril and St. Methodius ’- Veliko Tarnovo”. Digital Presentation and Preservation of Cultural and Scientific Heritage, vol. 6, Sept. 2016, pp. 267-74, https://doi.org/10.55630/dipp.2016.6.29.