Mell, Donald C.
Gale Research Company, 1982
Buku Referensi
Dieterich, Thomas G.
Center for Applied Linguistics, 1979
Buku Teks
Corcoran, Neil
Longman, 1993
Buku Teks
Attridge, Derek
Longman, 1982
Buku Teks
edited by Miriam K. Starkman
Alfred A. Knopf, 1967
Buku Teks