| #21 | Applications of Mathematics. -- Praha : Matematický ústav Akademie věd ČR, 1991-. -- ISSN 0862-7940 print. -- ISSN 1572-9109 online |
| #22 | Applied and environmental microbiology. -- Washington : American Society for Microbiology, 1976-. -- ISSN 0099-2240 print. -- ISSN 1098-5336 online |
| #23 | Applied categorical structures. -- Dordrecht : Kluwer Academic Publishers, 1993-. -- ISSN 0927-2852 print. -- ISSN 1572-9095 online |
| #24 | Applied geochemistry : Journal of the International Association of Geochemistry and Cosmochemistry. -- Oxford : Pergamon, 1986-. -- ISSN 0883-2927 print. -- ISSN 1872-9134 online |
| #25 | Applied physics express. -- Tokyo : Japan Society of Applied Physics, 2008-. -- ISSN 1882-0778 print. -- ISSN 1882-0786 online |
| #26 | Aquatic insects. -- Lisse : Swets & Zeitlinger, 1979-. -- ISSN 0165-0424 print. -- ISSN 1744-4152 online |
| #27 | Archiv für Hydrobiologie. -- Stuttgart : Schweizerbart, 1918-2006. -- ISSN 0003-9136 |
| #28 | Astronomy and astrophysics abstracts. -- Berlin : Springer, 1969-. -- ISSN 0067-0022 |
| #29 | The Astrophysical journal. -- Bristol : IOP Publishing, 1895-. -- ISSN 0004-637X print. -- ISSN 1538-4357 online |
| #30 | Atomic spectroscopy. -- Norwalk : Perkin/Elmer, 1980-. -- ISSN 0195-5373 |