Sclater, Neil, author
McGraw-Hill, 2011
Buku Teks
Angel, W. Larsen, author
McGraw-Hill, 2012
Buku Teks
Jenks, James M.
New Jersey : Alexander Hamilton Institute, Inc,
Buku Referensi
Klose, Paul S., author
Dow Jones-Irwin, 1989
Buku Referensi
Rifkin, Bernard, author
McGraw-Hill, 1979
Buku Teks