by DOBREVA,EKATERINA D.,BG, KARADACHKI,IVAN S.,BG, GAVRILOVA,MARIANA L.,BG, BOSEVSKI,VALENTIN M.,BG, ENCHEVA,MILKA A.,BG, PETROV,KHRISTO B.,BG, KIREV,SIMEON I.,BG, RADEV,SIMEON G.,BG, LIRKOV,ALEKSAND'R L.,BG
Year of Publication 15.08.1988