Building and Using A Business English Virtual Classroom: Lessons Learned. - Darina Dicheva; Ivanka Djakova; Yulia Bachvarova (Teleteaching, 1998)

User Interfaces for a Virtual Learning Environment: Two Study Cases. - Krassen Stefanov; Darina Dicheva; Roumen Nikolov; Ivanka Djakova (Educ. Inf. Technol., 1998)