Rago, Louis J.
Scranton: International, 1963
Buku Teks
Rage, Louis J., author
Scranton, Penn., International Textbook
Buku Teks
Riggs, James L., author
John Wiley & Sons, 1970
Buku Teks
Riggs, James L., author
John Wiley & Sons, 1987
Buku Teks
Moore, Franklin G., author
McGraw-Hill, 1969
Buku Teks