Connor, L.R.
Sir Isaac Pitman & Sons, 19--
Buku Teks
Huntsberger, David V., author
Allyn and Bacon, 1970
Buku Teks
Johnson, Palmer O., author
Prentice-Hall, 1953
Buku Teks
Prentice-Hall, 1997
Buku Teks
Agus Irianto, author
Prenada Media, 2004
Buku Teks