Todor Branzov, Krassimira Ivanova, Velichka Milousheva (2020). SERVICE APPROACH TO THE DEVELOPMENT OF ONLINE EDUCATIONAL PRODUCTS IN THE NATIONAL GEOINFORMATION CENTER OF BULGARIA. SGEM International Multidisciplinary Scientific GeoConference EXPO Proceedings; 20th International Multidisciplinary Scientific GeoConference Proceedings SGEM 2020, Informatics, Geoinformatics and Remote Sensing, 291-300. https://doi.org/10.5593/sgem2020/2.1/s07.038