Columbia subject headings:
Nuclear energy.
Oppenheimer, J. Robert, 1904-1967.
U.S. Atomic Energy Commission--Security measures.
Harvard subject headings:
Internal security--United States
Manhattan Project (U.S.)
Nuclear weapons--United States--20th century.
Oppenheimer, J. Robert, 1904-1967.
Physicists--United States--20th century.
Security clearances--United States.
U.S. Atomic Energy Commission--Officials and employees.
Princeton subject headings: