Naidoo, Jennie
Baillere Tindall , 2000
Buku Teks SO
Kemm, John
Macmillan, 1995
Buku Teks SO
Pender, Nola J.
Appleton & Lange, 1987
Buku Teks SO
Pender, Nola J.
Appleton & Lange, 1996
Buku Teks SO
Naidoo, Jenniem]
Bailliere Tindal Elsevier, 2011
Buku Teks SO