Argraffiad Saesneg gwreiddiol = Original English ed.: Llundain: Walker Books, 1991.
Addasiad Cymraeg gan = Welsh adaptation by: Emily Huws.
Cwac! by Martin Waddell. ISBN 186085348X. Published by Uned Iaith Genedlaethol Cymru CBAC in 1998. Publication and catalogue information, links to buy online and reader comments.