Coppock, Joseph D., author
McGraw-Hill, 1959
Buku Teks
Hodgetts, Richard M., author
Saunders, 1977
Buku Teks
Kolde, Endel J.
Prentice-Hall, 1968
Buku Teks
Veblen, Thorstein
New American Library, 1958
Buku Teks
McNaughton, Wayne L., author
John Wiley & Sons, 1960
Buku Teks