Darling, Annie, author
Harper, 2016
Buku Teks
Davis, F.T.
Institute for Business Planning, 1981
Buku Teks
Black, Kenneth, author
Prentice-Hall, 1988
Buku Teks
Cornell Paperbacks, 1971
Buku Teks
Gunther, John, 1901-1970, author
Harper & Brothers, 1960
Buku Teks