Effeithiau twristiaeth ar yr iaith Gymraeg yng ngogledd-orllewin Cymru = The effects of tourism on the Welsh language in north-west Wales by Dylan Phillips. ISBN 0947531319. Published by Canolfan Uwchefrydiau Cymreig a Cheltaidd Prifysgol Cymru in 2001. Publication and catalogue information, links to buy online and reader comments.