Hanke, John E., author
Pearson - Prentice Hall, 2009
Buku Teks
Hanke, John E., author
Prentice Halls, 2001
Buku Teks
Hanke, Jonh E., author
Pearson Prentice Hall, 2005
Buku Teks
Bratt, Elmer C., author
McGraw-Hill, 1958
Buku Teks
Stekler, Herman O., author
Frederick A. Praeger, 1970
Buku Teks