| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| A Text Telephone System in ISDN: Information Technologies and Sciences: Information Technologies and Sciences | 978-92-826-7500-7 (92-826-7500-9) | 1994 |
| COST 220: a Text Telephone Service for Europe | 978-92-826-6198-7 (92-826-6198-9) | 1993 |