Brown, Milon
Macmillan, 1956
Buku Teks
Terry, George Robert, author
Richard D. Irwin, 1982
Buku Teks
Luthans, Fred, author
McGraw-Hill , 1979
Buku Teks
Ficker, Victor B.
Charles E. Merrill, 1975
Buku Teks
Boyd, Branford B., author
McGraw-Hill , 1984
Buku Teks