Bowers, David A., author
Addison-Wesley, 1985
Buku Teks
Hansen, Alvin Harvey, 1887-1975, author
W.W. Norton, 1951
Buku Teks
edited by Shireen Hunter ; foreword by Robert G. Neumann and G. Henry M. Schuler
Westview Press, 1985
Buku Teks
Krooss, Herman Edward, 1912-1975, author
Prentice-Hall, 1966
Buku Teks
Vernon, Raymond, author
Free Press, 1989
Buku Teks