Gweithredu dros dwristiaeth : twristiaeth gynaliadwy ym Mharc Cenedlaethol Bannau Brycheiniog = Action for tourism : sustainable tourism in the Brecon Beacons National Park by Brecon Beacons National Park Authority. Published by Brecon Beacons National Park in 2004. Publication and catalogue information, links to buy online and reader comments.