Friedrich, Carl J., author
Prederick A. Praeger, 1965
Buku Teks
Friedrich, Carl J., author
Frederick A. Praeger, 1962
Buku Teks
Barbu, Zevedei, author
Routledge , 1965
Buku Teks
Skidmore, Monique, author
ANU E Press, 2008
Buku Teks
McClosky, Herbert, author
McGraw-Hill, 1960
Buku Teks