Hartley, W.C.F.
Business Books Ltd. , 1976
Buku Teks
Niece, E.H. Mac, author
John Wiley & Sons, 1961; 1957
Buku Teks
Wadsworth, 1962
Buku Teks
Brown, Robert G., author
McGraw-Hill, 1959
Buku Teks
Makridakis, Spyros G., author
The Free Press, 1990
Buku Teks