Entities
- Uffizien <Florenz>
- Letter from: 22.9.1932, Florence (Italy)
- Union Oil Company
- Letter from: 16.9.1955, Tacoma (Wash.)
- United Air Lines <Chicago>
- Letter from: 31.5.1952, Auf dem Flug nach Hawaii
- Letter from: 3.6.1952, Maui (Hawaii)
- Letter from: 13.12.1952, Auf dem Flug nach New York
- United Nations <New York>
- Letter from: 17.6.1950, San Francisco (Calif.)
- Letter from: 18.7.1951, New York
- Letter from: 22.12.1952, New York (N.Y.)
- Letter from: 28.12.1952, New York (N.Y.)
- Letter from: 31.12.1952, New York (N.Y.)
- Universität Heidelberg, Institut für Krebsforschung
- Letter from: 11.8.1922, Schönwald im Schwarzwald (Germany)
- Letter from: 16.8.1922, Schönwald im Schwarzwald (Germany)
- University of California <Berkeley>
- Letter from: 7.12.1941, New York (N.Y.)
- Letter from: 13.4.1942, New York (N.Y.)
- Letter from: 17.4.1942, San Francisco
- Letter from: 21.4.1942, San Francisco
- Letter from: 23.4.1942, San Francisco
- Letter from: 26.4.1942, San Francisco
- Letter from: 30.4.1942, San Francisco
- Letter from: 26.5.1944, New York
- Letter from: 28.10.1945, San Francisco
- Letter from: 7.11.1945, San Francisco
- Letter from: 23.1.1948, Washington
- Letter from: 4.6.1952, San Francisco
- Letter from: 5.3.1953, Dallas
- University of London
- Letter from: 4.1.1935, London (England)
- University of North Carolina <Chapel Hill>
- Letter from: 30.6.1949, Amenia, N.Y.
- Letter from: 2.2.1950, San Francisco (Calif.)
- Letter from: 6.2.1950, Chapel Hill
- Letter from: 7.2.1950, Raleigh, North Carolina
- Universum Film-A.G. <Berlin> [Ufa]
- Letter from: 7.7.1922, Charlottenburg
- Letter from: 9.10.1924-10.10.1924, an Board
- Letter from: 23.12.1929, Berlin (Germany)
- Useful women <London>
- Letter from: 6.10.1938, Penrhyndeudraet /North Wales