Johnson, George B., author
McGraw-Hill, Higher Education, 2008
Buku Teks
Stanier, Roger Y., author
Prentice-Hall, 1963
Buku Teks
Gregory, J. N., author
Angus & Robertson , 1966
Buku Teks
Johnson, George B., author
McGraw-Hill, 2003
Buku Teks
Toynbee, Arnold J., author
Oxford University Press, 1957
Buku Teks