Veblen, Thorstein
New American Library, 1958
Buku Teks
McNaughton, Wayne L., author
John Wiley & Sons, 1960
Buku Teks
Kappel, Frederick R., 1902-
McGraw - Hill , 1960
Buku Teks
Passerini, Katia, author
[Springer, ], 2012
eBooks
Paul, Dan, author
John Wiley & Sons, 2003
Buku Teks