Title: Dokumenti i materiali za sŭtrudnichestvo mezhdu Bŭlgarskata komunisticheska partii︠a︡ i Germanskata edinna sot︠s︡ialisticheska partii︠a︡, 1977-1984
Subjects: Bŭlgarska komunisticheska partii︠a︡, International cooperation, Communist parties, Sozialistische Einheitspartei Deutschlands, Sources, History