Arg. Saesneg gwreiddiol = Original English ed.: Cheltenham: Stanley Thornes (Publishers) Ltd, 1996.
Yn cynnwys mynegai = Includes index.
Systemau gwybodaeth by Stephen Doyle. ISBN 1860853153. Published by Uned Iaith Genedlaethol Cymru CBAC in 1998. Publication and catalogue information, links to buy online and reader comments.