Arg. Saesneg gwreiddiol = Original English ed: London: Harcourt Brace Jovanovich, 1992.
Cyhoeddwyd dan nawdd Cynllun Adnoddau Cyd-bwyllgor Addysg Cymru = Published under the auspices of the Welsh Joint Education Committee Resources Project.
Mathemateg HBJ. ISBN 0003005739. Published by Collins Educational in 1995. Publication and catalogue information, links to buy online and reader comments.