| title | ISBN-13 | year of publica- tion | other author(s) |
|---|---|---|---|
| A Concise Comparative Celtic Grammar | 978-3-525-26102-6 | 1989 | Henry Lewis |
| Road-map to the Indian's Treasure | 978-87-7114-440-6 | 2012 | |
| Ung Sprogforsker Pa Rejse V. 7 (Danish Humanist Texts & Studies) | 978-87-7289-276-4 | 1994 | |
| Vergleichende Grammatik der keltischen Sprachen | 978-3-525-26119-4 | 1976 | |
Books On Demand · Museum Tusculanum Press · Vandenhoeck & Ruprecht