Arg. Saesneg gwreiddiol = Original English ed.: Llundain: Pavilion Books, 1997.
Addasiad Cymraeg gan = Welsh adaptation by: Gwen Redvers Jones.
Gêm gyfeillgar by Michael Foreman. ISBN 1860853676. Published by Uned Iaith Genedlaethol Cymru CBAC in 1999. Publication and catalogue information, links to buy online and reader comments.