Arg. Saesneg gwreiddiol = Original English ed.: Llundain: Macmillan Children's Books, 1999.
Addasiad Cymraeg gan = Welsh adaptation by: Gwynne Williams.
Y gryffalo by Julia Donaldson. ISBN 1855963442. Published by Gwasg y Dref Wen. Publication and catalogue information, links to buy online and reader comments.