Goatly, Andrew
Routledge , 2000
Buku Referensi
Rosenberg, Vivian M.
Random House, 1989
Buku Teks SO
Barnet, Sylvan
Bedford/St. Martin's, 2002
Buku Teks SO
Barnet, Sylvan
Bedford/St Martin's, 2014
Buku Teks SO
Gardner, Peter S.
St. Martin's Press , 1996
Buku Teks SO