Arg. Cymraeg gwreiddiol = Original Welsh edition: 1999.
Addasiad Cymraeg = Welsh adaptation: Iola Alban.
Camu ymlaen mewn addysg grefyddol. llyfr 1 by Michael Keane. ISBN 1853571431. Published by Canolfan Genedlaethol Addysg Grefyddol in 2001. Publication and catalogue information, links to buy online and reader comments.