Columbia subject headings:
Harvard subject headings:
Statesmen--Bulgaria--Correspondence.
Princeton subject headings:
Bulgaria--Politics and government--1944-1990.
Dimitrov, Georgi, 1882-1949--Correspondence.
Kolarov, Vasil Petrov, 1877-1950--Correspondence.
Petkov, Nikola D. (Nikola Dimitrov), 1892 or 1893-1947--Correspondence.
Politicians--Bulgaria--Correspondence.