Stephan, John J.
Stanford University Press, 1994
Buku Teks
Moorehead, Alan, author
Harper and Brother, 1958
Buku Teks
Woytinsky, W.S.
Vanguard Press, 1961
Buku Teks
Deutscher, Isaac
Oxford University Press, 1967
Buku Teks
Carr, E.H. (Edward Hallet), author
Macmillan, 1950-1953
Buku Teks