| Letras: an architecture and framework for ubiquitous pen-and-paper interaction Recent countries visiting this post |  |
 | 6 | United States |
 | 1 | |
 | 1 | India |
| Letras: an architecture and framework for ubiquitous pen-and-paper interaction Recent countries visiting this post | |
| 6 | United States |
| 1 | |
| 1 | India |