Argraffiad Saesneg gwreiddiol = Original English edition : Oxford : Rigby, 2001.
Addasiad Cymraeg gan Awdurdod Cymwysterau, Cwricwlwm ac Asesu Cymru = Welsh adaptation by Qualifications, Curriculum and Assessment Authority for Wales.
Ffocws rhifedd 1 : problem yr wythnos. ISBN 1904837050. Published by Rigby in 2004. Publication and catalogue information, links to buy online and reader comments.