| #21 | Acta mathematica Hungarica. -- Budapest : Akadémiai Kiadó, 1983-. -- ISSN 0236-5294 print. -- ISSN 1588-2632 online |
| #22 | Acta mathematica Sinica. -- Beijing : Shùxué xuébào biānjí wǎiyuánhuì, 1952-. -- ISSN 0583-1431 |
| #23 | Acta mathematica Universitatis Comenianae. -- Bratislava : Comenius University Press, 1980-. -- ISSN 0862-9544 print. -- ISSN 1336-0310 online |
| #24 | Acta Mathematica Universitatis Ostraviensis. -- Ostrava : Přírodovědecká fakulta Ostravské univerzity, 2004-2009. -- ISSN 1214-8148 |
| #25 | Acta mathematica Vietnamica. -- Hanoi : Institut de mathématiques, 1976-. -- ISSN 0251-4184 |
| #26 | Acta mechanica. -- Wien : Springer, 1965-. -- ISSN 0001-5970 print. -- ISSN 1619-6937 online |
| #27 | Acta physica Slovaca. -- Bratislava : Fyzikálny ústav SAV, 1973-. -- ISSN 0323-0465 print. -- ISSN 1336-040X online |
| #28 | Acta polytechnica, Civil engineering and building construction series. -- Stockholm : Acta polytechnica publishing office, 1946-1957. -- ISSN 0365-561X |
| #29 | Acta polytechnica, Electrical engineering series. -- Stockholm : Acta polytechnica publishing office, 1946-1957. -- ISSN 0375-8400 |
| #30 | Acta polytechnica, Chemistry including metallurgy series. -- Stockholm : Acta polytechnica publishing office, 1947-1956. -- ISSN 0375-8362 |