Arg Saesneg gwreiddiol = Original English ed: London: A. & C. Black, 1987.
Addasiad Cymraeg gan = Welsh adaptation by: Cynthia Saunders Davies.
Silvia o Beriw by Sarita Kendall. ISBN 090483655X. Published by Ivan Corbett in 1990. Publication and catalogue information, links to buy online and reader comments.