Keywords: Bakhmeteff Archive of Russian and East European History and Culture ; Catalogs ; Soviet Union ; Civilization ; Sources ; Bibliography ; Catalogs ; Europe, Eastern ; Civilization ; 20th century ; Sources ; Bibliography ; Catalogs ; Columbia University ; Rare Book and Manuscript Library ; Catalogs ; Katalog ; Bibliografie ; Quelle ; Bakhmeteff Archive of Russian and East European History and Culture ; Sowjetunion ; Exil ; Geschichte 1920-1980 ; Osteuropa ; Exil ; Rare Book and Manuscript Library ; Osteuropa ; Geschichte ; Rare Book and Manuscript Library ; Russland ; Geschichte