editor, Philip Babcock Gove
Merriam-Webster, 1993
Buku Referensi
Merriam-Webster Inc., 1988
Buku Referensi
Bolander, Donald O., author
Lexicon Publication, 1993
Buku Referensi
Lexicon Publication, 1993
Buku Referensi
Groiler
Grolier Incorporated, 1992
Buku Referensi