Greenwich House, 1988
Buku Teks
Alexandrescu, Vasile
Military Pub. House, 1985
Buku Teks
Deborin, G., author
Progress Publishers, 1979
Buku Teks
Brogan, D.W. (Denis William), author
Harcourt, Brace & World, 1963
Buku Teks
Friedrich, Carl J.
Rinehart, 1948
Buku Teks