Arg. Saesneg gwreiddiol = Original English ed.: Llundain: Orchard Books, 1999.
Addasiad Cymraeg gan = Welsh adaptation by: Emily Huws.
Teitl clawr = Cover title.
Testun a lluniau ar y cloriau mewnol = Text and illustrations on inside covers.
Cysga wir, Heulwen by Jane Simmons. ISBN 185902730X. Published by Gwasg Gomer in 1999. Publication and catalogue information, links to buy online and reader comments.