Cleveland, Ohio, Lincoln Extension Institute
Buku Teks
Ian Beardwell, Len Holden
Prentice-Hall, 2001
Buku Teks
Fitz-enz, Jac, author
McGraw-Hill, 2001
Buku Teks
Mike Millmore, Philip Lewis, Mark Saunders, Adrian Thornhill, Trevor Morrow
Prentice-Hall, 2007
Buku Teks
by John H. Hollenbeck [and others]
McGraw-Hill, 2009
Buku Teks