| title | author | publisher | year | bookcover |
|---|---|---|---|---|
| Logistiek - Geformaliseerde Logica | Prof. Dr. R. Feys | Filosofische Bibliotheek | 1944 |  |
| title | author | publisher | year | language | softcover |
|---|---|---|---|---|---|
| DICTIONARY OF SYMBOLS OF MATHEMATICAL LOGIC | edited by ROBERT FEYS and FREDERIC B. FITCH | NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAM | 1969 | ENGLISH | x |