Lewis, Richard J., author
Wiley-Interscience, 2002
Buku Referensi
editors, Gerald P. Koocher, John C. Norcross, Sam S. Hill, III
Oxford University Press, 2005
Buku Teks
Merriam-Webster, 1995
Buku Referensi
Houghton Miffiln, 1981
Buku Referensi
editor, Gerald P. Koocher, John C. Norcross, Sam S. Hill
Oxford University Press, 2005
Buku Referensi