Arg. Saesneg gwreiddiol = Original English ed.: Cheltenham: Stanley Thornes, 1981.
Addasiad Cymraeg gan = Welsh adaptation by: Dafydd Kirkman.
Mecaneg by Roger Muncaster. ISBN 185644922X. Published by Y Ganolfan Astudiaethau Addysg in 1995. Publication and catalogue information, links to buy online and reader comments.