Title: The Gaelic-English Dictionary / Edition 1, Author: Colin B.D. Mark
Title: Intermediate Irish: A Grammar and Workbook / Edition 1, Author: Nancy Stenson
Title: The Celtic Languages / Edition 1, Author: Martin Ball
Title: Modern Welsh: A Comprehensive Grammar / Edition 3, Author: Gareth King
Title: The Welsh Learner's Dictionary, Author: Heini Gruffudd
Title: Colloquial Breton / Edition 1, Author: Herve Ar Bihan