Croesi ffiniau : Cip ar rai o wledydd bychain Ewrop trwy gyfrwng y Gymraeg fel ail iaith : Llyfr athrawon by Non ap Emlyn. ISBN 1856449106. Published by Athrofa Addysg Uwch Gogledd-Ddwyrain Cymru in 1994. Publication and catalogue information, links to buy online and reader comments.