Fisher, Douglas
Ill. Irwin, 1971
Buku Teks
Luckett, Dudley G., author
McGraw-Hill , 1984
Buku Teks
Pesek, Boris P., author
Harvester. Wheatshaf, 1988
Buku Teks
Poole, William, author
Addison-Wesley, 1979
Buku Teks
Keynes, John Maynard, author
A Harvest book, 1949
Buku Teks