Taylor, John B., 1946-, author
South Western Cengage Learning, 2012
Buku Teks
Sloman, John, author
Harvester Wheatsheaf, 1994
Buku Teks
Fairchild, Fred Rogers, author
Macmillan, 1940
Buku Teks
Fairchild, Fred Rogers, author
Macmillan, 1947
Buku Teks
Lipsey, Richard G., 1928-, author
Harper & Row, 1981
Buku Teks