Argraffiad Saesneg gwreiddiol = Original English edition : Oxford : Oxford University Press, 1991.
Addasiad Cymraeg gan = Welsh adaptation by : Juli Paschalis.
Y blwch mawr by Roderick Hunt. ISBN 0861742044. Published by Gwasg Addysgol Drake in 1998. Publication and catalogue information, links to buy online and reader comments.