by ZAKHARIEV,PETR D, MILENKOV,SVETOSLAV JJ
Year of Publication 15.03.1984

by KRSTEV,KHRISTO S, PETROVA,LJUBKA A, ZAKHARIEV,PETR D, PRVANOV,PRIMO N
Year of Publication 15.07.1987

by KRSTEV,KHRISTO S, PETROVA,LJUBKA A, ZAKHARIEV,PETR D, PRVANOV,PRIMO N
Year of Publication 15.10.1985

by GROZDANOV,VELCHO D, ZAKHARIEV,PETR D, VASILEV,GERASIM C, KOVACHEV,NIKOLA G, KAROV,KALIN V
Year of Publication 14.01.1983

by KRSTEV,KHRISTO S, PETROVA,LJUBKA A, ZAKHARIEV,PETR D, DOMBALOVA,LILJANA C, PRVANOV,PRIMO N, LICHEV,ROMAN P
Year of Publication 15.02.1984

by KHRUHHOV,NIKOLAJJ A, KLEPIKOV,JURIJJ B, BOZHKOV,BOZHIDAR N, ZAKHARIEV,PETR D, KAROVA,DOBRINKA G, TODOROVA,MARIJA I, STOJJCHEVA,ROSICA M, TODOROV,MITKO I, SKOROPAD,VLADIMIR M, KAROV,KALIN V, KASHURKO,ALEKSANDR S
Year of Publication 16.12.1984

by KRSTEV,KHRISTO S, ZAKHARIEV,PETR D, PRVANOV,PRIMO N, LICHEV,ROMAN P
Year of Publication 15.08.1983

by ZAKHARIEV,PETR D, KRSTEV, KHRISTO S, PRVANOV,PRIMO N, PARASHKEVOV,IVAN K, SULTANOV,GEORGI I
Year of Publication 15.03.1983

by POPOV,ANGEL JJ.,BG, ZAKHARIEV,PET'R D.,BG, PETROVA,LJUBKA A.,BG
Year of Publication 15.03.1989