Arg Saesneg gwreiddiol = Original English ed: Leckhampton: Stanley Thornes, 1985.
Yn cynnwys mynegai = Includes index.
Egni : pynciau dethol by J. J. Wellington. ISBN 187280814X. Published by D. Brown a'i Feibion mewn cydweithrediad â Stanley Thornes in 1991. Publication and catalogue information, links to buy online and reader comments.