Arg. Saesneg gwreiddiol = Original English ed.: Llundain: Transworld Publishers Ltd, 1993.
Addasiad Cymraeg gan = Welsh adaptation by: Iola Jôns.
Helynt y twll yn y wal by Malorie Blackman. ISBN 1870206320. Published by Honno in 1999. Publication and catalogue information, links to buy online and reader comments.