Rio, Helmi, author
Times Editions, 1995
Buku Referensi
Murry, John Middleton, author
Oxford University Press, 1956
Buku Teks
Szuchman, Lenore T., author
Wadsworth, 2014
Buku Teks
Murphy, Beverly, author
McGraw-Hill, 2005
Buku Referensi
Strunk, William
Macmillan, 1959
Buku Teks