Hodgson, Ernest
Elsevier, 1987
Buku Teks SO
Tanenbaum, Albert
McGraw-Hill, 1951
Buku Teks SO
Arnold, part of the Hodder Headline group, 2018
Majalah, Jurnal, Buletin
edited by Bryan Ballantyne, Timothy Marrs and Paul Turner
Macmillan, 1995
Buku Teks SO
Aldridge, W. Norman
Taylor and Francis, 1996
Buku Teks