Arg Saesneg gwreiddiol = Original English ed: London: Harcourt Brace Jovanovich, 1990.
Mathemateg HBJ : llyfr Gweithgareddau Blwyddyn 1: Hetiau,cathod ac ystlumod/Siopau. ISBN 0746604432. Published by Harcourt Brace Jovanovich in 1992. Publication and catalogue information, links to buy online and reader comments.