Salmon, Charles G.
Harper and Row, 1980
Buku Referensi
Ambrose, James E.
John Wiley & Sons, 1997
Buku Teks
Ambrose, James E.
John Wiley & Sons, 2007
Buku Teks
Grinter, Linton E. (Linton Elias), 1902-
Macmillan, 1963
Buku Teks
Englekirk, Robert
John Wiley & Sons, 1994
Buku Teks