Columbia subject headings:
Harvard subject headings:
Astronautics--Soviet Union--History
Gagarin, Yuri Alekseyevich, 1934-1968
Korolev, Sergeĭ Pavlovich, 1907-1966
Manned space flight--History
Princeton subject headings:
Astronautics--Soviet Union--History.
Astronauts--Soviet Union--Biography.
Gagarin, Yuri Alekseyevich, 1934-1968.
Korolev, Sergeĭ Pavlovich, 1907-1966.