Lopez, Alan D., author
WHO, 1984
Buku Teks
Thomlinson, Ralph
Random House, 1965
Buku Teks
Thomlinson, Ralph
California State University, 1976
Buku Teks
Thomlinson, Ralph, author
Random House , 1976
Buku Teks
Thomlinson, Ralph, author
Dickenson Publishing, 1975
Buku Teks