Letters from Zemun city authorities, South Slavic Choral Union, Sokolsko society, Sport Club Trade youth, Craftsmen-trade Society from Bačka Palanka, Serbian Choral Society "Gusle"; letters to South Slavic Choral Union, Radio-Belgrade, Serbian Choral Society from Veliki Bečkerek, Serbian Choral Society "Gusle"; membership applications; concert invitations. Creator(s): unknown.