Bryson, Bill, author
Penguin Books, 1987
Buku Referensi
edited by Frank O. Colby
Thomas Y. Crowell, 1950
Buku Referensi
Saussy, George Stone, author
Penguin Books, 1986
Buku Referensi
Donaldson, Bruce, author
Routledge, 2004
Buku Referensi
edited by David Nelson
Penguin Books, 2003
Buku Referensi