Walters, Morgan L
N.Y.Holt Rinehart and Winston,inc, 1966
Buku Teks
editor, William Morris
Houghton Miffiln, 1976
Buku Referensi
Victoria Neufeldt, David B. Guralnik, editor
Webster's New World, 1988
Buku Referensi
Diamond, 2001
Buku Referensi
Eckersley, C. E. (Charles Ewart), 1892-1967, author
Longmans, Green and Co., 1953
Buku Referensi