Argraffiad Saesneg gwreiddiol = Original English edition: Oxford : Oxford University Press, 1997.
Addasiad Cymraeg gan = Welsh adaptation by: Juli Paschalis.
Yr herwgipwyr by Jacquie Buttriss. ISBN 086174330X. Published by Gwasg Addysgol Drake in 2000. Publication and catalogue information, links to buy online and reader comments.