Artikel Jurnal
Nollen, Stanley D.
New York Amacon c.1978,
Buku Teks
Lieu, D.K.
Rutgers University Press, 1948
Buku Teks
Abhyankar, K.D.
Tata McGraw-Hill, 1992
Buku Teks
Eisenhower, Dwight D.
Federal Register Division, National Archives and Records Service, 1958
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