Johnson, Carol, author
Allen and Unwin, 1989
Buku Teks
Morgan, Chester A., author
The Dorsey Press, 1962
Buku Teks
Chamberlain, Neil W. (Neil Wolverton), author
McGraw-Hill , 1980
Buku Teks
Borjas, George J., author
McGraw-Hill, 2010
Buku Teks
Sloane, Arthur A., author
Prentice-Hall, 1977
Buku Teks