Barnes, James F., author
St. Martin`s Press, 1980
Buku Teks
Friedmann, Wolfgang, 1907-1972, author
Macmillan, 1951
Buku Teks
Soltau, Roger H.
Longmans, Green , 1951
Buku Teks
Soltau, Roger H.
Longmans, Green , 1960
Buku Teks
Kegley, Charles W. (Charles William), Jr., author
Wadsworth, 2009
Buku Teks