Gross, Lynne Schafer
Iowa WCB , 1989
Buku Teks
Sherman, Barry L., author
McGraw-Hill, 1995
Buku Teks
Bittner, John R., 1943-, author
Prentice-Hall, 1985
Buku Teks
Martin, James, author
Prentice-Hall, 1977
Buku Teks
Shepard, Steven, author
McGraw Hil , 2014
Buku Teks