Steiner, William Howard
Henry Holt, 1956
Buku Teks
Luckett, Dudley G.
McGraw-Hill , 1984
Buku Teks
Bradford, Frederick A.
Longmans, Green, 1939
Buku Teks
Bradford, Frederick A.
Longmans, Green, 1933
Buku Teks
Savage, Donald T.
John Wiley & Sons, 1977
Buku Teks