Carr, Joseph J.
Tab Books, 1982
Buku Referensi
Dollhoff, Terry
Reston Pub., 1979
Buku Teks
Ghani, Noordin
Research Study Press, 1980
Buku Teks
Byers, T.J.
Micro Text/McGraw-Hill Copublication, 1983
Buku Teks
Dixey, Graham
Stanley Thornes, 1991
Buku Teks