by GEORGIEV, VALENTIN G, BOGOEV, IVAN G, DONCHEV, STEFAN D
Year of Publication 15.08.1994

by DONCHEV,STEFAN D, VCHEV,KOSTADIN D, KOLEVA,KIRILKA B
Year of Publication 15.01.1986

by POPOV, GEORGI J, KOLEVA, KIRILKA B, VELEVA, MARIANA N, DONCHEV, STEFAN D
Year of Publication 15.11.1989

by DONCHEV,STEFAN D, GEORGIEV,PETR A, BATEV,KRSTIN P, VENKOVA,EVGENIJA V
Year of Publication 15.05.1985

by TSANEV, VICHKO I, ANGELOVA, MAGDALENA D, VELEVA, MARIANA N, DISHKOV, PETAR S, PENCHEV, STOJAN P, KUZNETSOV, ANDRIAN I, OMELJANCHUK, ALEKSEJ M, USHAKOV, ALEKSANDR I, DONCHEV, STEFAN D
Year of Publication 15.10.1991

by BATEV,KR'STIN P.,BG, GEORGIEV,PET'R A.,BG, DONCHEV,STEFAN D.,BG, KOLEV,BISER G.,BG
Year of Publication 15.04.1988

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
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by DISHKOV,PETR S, CANEV,VICHO I, DONCHEV,STEFAN D
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by KOZHUKHAROV,VLADIMIR S, DONCHEV,STEFAN D, NIKOLOV,SERAFIM M, MARINOV,MARIN R, GRIGOROVA,GIZELA E
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by KOZHUKHAROV,VLADIMIR S, PAVLOVA,JULIJA N, DONCHEV,STEFAN D, NIKOLOV,SERAFIM M, MARINOV,MMARIN R, GRIGOROVA,GIZELA E
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