Neil, A. B.
Oxford University Press , 1974
Buku Teks
Murphy, Henry C., author
McGraw-Hill, 1950
Buku Teks
Saw, Swe Hock
University of Pensylvania Press, 1970
Buku Teks
Hough, Jerry F.
The Brookings Institution, 1980
Buku Teks
Kesselman, Mark
D.C. Health an Company, 1987
Buku Teks