Plano, Jack C.
Holt, Rinehart and Winston, 1985
Buku Referensi
Kenyon, John Samuel
Merriam-Webster ; G. & C. Merriam Co., 1953
Buku Referensi
Charles Scribner's Sons , 1981
Buku Referensi
edited by Edward Conrad Smith and Arnold John Zurcher
Barnes & Noble, 1966
Buku Teks SO
Mellinkoff, David
[Publisher not identified], 1992
Buku Teks