Jackson, J. Hampden, author
Cambridge University Press, 1941
Buku Teks
Barbier, Frederic, author
Polity Press, 2017
Buku Teks
Reimann, Mathias, 1955-, author
Transnational Publishers, 1995
Buku Teks
Frederick A. Praeger, 1967
Buku Teks
Coats, Willson H.
McGraw-Hill, 1966
Buku Teks