Argraffiad Saesneg gwreiddiol = Original English edition : London : A & C Black Publishers, 2001.
Addasiad Cymraeg gan = Welsh adaptation by : Gwawr Maelor.
Selsig a'r ysbrydion by Michaela Morgan. ISBN 9781843235507. Published by Gwasg Gomer in 2006. Publication and catalogue information, links to buy online and reader comments.