edited by Andrew Blowers, Chris Hammett and Philip Sarre
Hutchinson Educational in association with the Open University Press, 1974
Buku Teks
Outhwaite, William, author
Blackwell, 2006
Buku Teks
Friedmann, Wolfgang, 1907-1972, author
Geroge Braziller, 1971
Buku Teks
edited by John J. McIntyre
National Defense University Press, 1979
Buku Teks
Giphart, Ronald
Kwadraat, 1997
Buku Teks