Argraffiad Saesneg gwreiddiol = Original English edition : London : Hutchinson Educational, 1987.
Addasiad Cymraeg gan = Welsh adaptation by : Lynwen Jones.
Bioleg safon uwch. Cyfrol 3, Egnïeg ac ensymau by Glenn Toole. ISBN 1856444007. Published by Canolfan Astudiaethau Addysg in 1999. Publication and catalogue information, links to buy online and reader comments.