by DASKALOV,DZHENKO I.,BG, ILIEV,STOJAN I.,BG, MIKHAJJLOV,MIROSLAV D.,BG, DEMIREV,ZHIVKO JJ.,BG, KOVACHEV,NIKOLA G.,BG, TODOROV,TODOR D.,BG, MIRASCHIEV,BORIS S.,BG
Year of Publication 16.01.1989