Argraffiad Saesneg gwreiddiol = Original English edition : Oxford : Rigby, 2000.
Addasiad Cymraeg gan Awdurdod Cymwysterau, Cwricwlwm ac Asesu Cymru = Welsh adaptation by Qualifications, Curriculum and Assessment Authority for Wales.
Ffocws rhifedd 6 : llyfr ffocws dosbarth by Sheila Ebbutt. ISBN 0948469943. Published by Gwasg Taf in 2003. Publication and catalogue information, links to buy online and reader comments.