Wilhite, Virgle Glenn
Bookman Associates , 1958
Buku Teks
Mason, Alpheus Thomas,1899-1989, author
Cornel University Press, 1955
Buku Teks
Rose, John David, author
Authorhouse, 2005
Buku Teks
Hofstadter, Richard
George Braziller, 1959
Buku Teks
Gettell, Raymond G.
Appleton-Century-Crofts, 1928
Buku Teks