Smykey, Edward W.
Macmillan, 1961
Buku Teks
James A. Tompkins, Dale A. Harmelink [editors]
McGraw-Hill, 1994
Buku Referensi
Constantin, James A.
Appleton-Century-Crofts, 1966
Buku Teks
Jones, james V.
McGrawHill, 1994
Buku Referensi
Heskett, J.L.
The Ronald Press Comp., 1964
Buku Teks