by KOLEV,BISER G, BOJJKOVA,KHRISTINA N
Year of Publication 14.05.1982

by BOJJKOVA,KHRISTINA N, PANDUROVA,VIKTRIJA P
Year of Publication 15.02.1982

by KOLEV,BISER G, JAKIMOV,TIKHOMIR N, DONCHEV,STEFAN D, KOLEV,NIKOLA T, BOJJKOVA,KHRISTINA N, GEORGIEV,PETR A, BATEV,KRSTIN P, VCHEV,KOSTADIN D
Year of Publication 15.11.1984

by KOLEV,BISER G, JAKIMOV,TIKHOMIR N, DONCHEV,STEFAN D, KOLEV,NIKOLA T, BOJJKOVA,KHRISTINA N, GEORGIEV,PETR A, VCHEV,KOSTADIN D, BATEV,KRSTIN P
Year of Publication 15.10.1984

by JAKIMOV,TIKHOMIR N, KOLEV,BISER G, BOJJKOVA,KHRISTINA N
Year of Publication 15.07.1982

by KOLEV,BISER G, BOJJKOVA,KHRISTINA N, JAKIMOV, TIKHOMIR N, VELCHEV,VALENTIN L
Year of Publication 16.05.1983