Columbia subject headings:
Aeronautics--Soviet Union--History.
Astronautics--Soviet Union--History.
Astronauts--Soviet Union--Biography.
Gagarin, Yuri Alekseyevich, 1934-1968.
Harvard subject headings:
Princeton subject headings:
Aeronautics--Soviet Union--History.
Astronautics--Sovient Union--History.
Astronauts--Soviet Union--Biography.
Gagarin, Yuri Alekseyevich, 1934-1968.