Braff, Allan J.
John Wiley & Sons, 1969
Buku Teks
Boulding, Kenneth Ewart, 1910-1993
Harper & Row, 1966
Buku Teks SO
Ferguson, C.E.
Richard D. Irwin, 1966
Buku Teks SO
Addison-Wesley, 1985
Buku Teks SO
Jehle, Geoffrey A.
Prentice-Hall, 1991
Buku Teks