| title | media type | ISBN-13 | year of publication |
|---|---|---|---|
| Alien Investigator: Case Files of Britain's Leading UFO Detective | Hardcover | 978-0-7472-2285-9 | 1999 |
| Alien Investigator: The Case Files of Britain's Leading UFO Detective | Paperback | 978-0-7472-6141-4 | 1999 |
| PROLOG: A Logical Approach | " | 978-0-19-853821-9 | 1990 |
| PROLOG: A Logical Approach | Hardcover | 978-0-19-853822-6 | 1990 |
| The Life and Thought of Siger of Brabant, Thirteenth-Century Parisian Philosopher: An Examination of His Views on the Relationship of Philosophy and Theology | " | 978-0-7734-8477-1 | 1998 |
Edwin Mellen Pr · Headline · Oxford University Press