5,250 titles
| Acta Oeconomica | 1966-1995 | Budapest, Hungary |
| Acta Orientalia | 1950-2000 | Budapest, Hungary |
| Acta Paediatrica | 1960-1994 | Budapest, Hungary |
| Acta Physica | 1951-1994 | Budapest, Hungary |
| Acta Physiologica | 1950-1999 | Budapest, Hungary |
| Acta Phytopathologica et Entomologica | 1966-2001 | Budapest, Hungary |
| Acta Technica | 1950-1997 | Budapest, Hungary |
| Acta Technica Napocensis | 1994-2001 | Cluj-Napoca, Romania |
| Acta Universitatis Szegediensis - Acta Historiae Litterarum Hungaricarum | 1958-2006 | Szeged, Hungary |
| Acta Veterinaria | 1951-1998 | Budapest, Hungary |
| Acta Zoologica | 1954-2002 | Budapest, Hungary |
| Acțiunea | 1935-1939 | Sibiu, Romania |
| Actualitatea | 1914-1928 | Bucharest, Romania |
| Adalékok Zemplénvármegye történetéhez | 1895-1926 | Sátoraljaújhely, Hungary |
| Adelaidei Magyar Értesítő | 1968-1997 | Norwood, United States of America |
| Adevărul | 1888-1950 | Bucharest, Romania |
| Adevěrul Literar şi Artistic | 1921-1939 | Bucharest, Romania |
| Administraţia Română | 1923-1940 | Cluj-Napoca, Romania |
| Administraţia Românească Nouă | 1939-1941 | Bucharest, Romania |
| Adressbuch der k. freien Stadt Hermannstadt | 1882-1911 | Sibiu, Romania |
