Cyhoeddwyd yn wreiddiol = Originally published: USA: Harper and Row, 1963.
Cyhoeddiad Cymraeg Cyntaf = First Welsh publication: 1988.
Yng ngwlad y pethau gwyllt by Maurice Sendak. ISBN 9781855969834. Published by Gwasg y Dref Wen in 2013. Publication and catalogue information, links to buy online and reader comments.