Walters, Morgan L
N.Y.Holt Rinehart and Winston,inc, 1966
Buku Teks
Walters, Margan L
N.Y.Holt,Rinehart and winston,ic, 1966
Buku Teks
Kenyon, John Samuel
Merriam-Webster ; G. & C. Merriam Co., 1953
Buku Referensi
edited by Jess Stein
Random House, 1961
Buku Referensi
Holt, Rinehard and Winston, Inc.
Holt, Rinehart and Winston,Inc, 1966
Buku Teks