Yearsley, R.B.
Gower Press, 1974
Buku Referensi
Siswanto
Elex Media Komputindo, 1990
Buku Teks SO
Erikson, Warren J.
Addison-Wesley, 1986
Buku Teks SO
Flower, John
Accountancy Age Books, 1973
Buku Teks SO
Schwefel, Hans-Paul
John Wiley & Sons, 1977
Buku Teks SO