McLeod, John, author
Sage Publications, 2002
Buku Teks
Claringbull, Norman, author
Learning Matters, 2010
Buku Teks
Claringbull, Norman, author
Learning Matters, 2011
Buku Teks
Bager-Charleson, Sofie, author
Learning Matters, 2011
Buku Teks
Colin Lago, editor
McGraw-Hill, 2011
Buku Teks