| #641 | K-theory. -- Dordrecht : Reidel, 1987-. -- ISSN 0920-3036 print. -- ISSN 1573-0514 online |
| #642 | Kibernetika i sistemnyj analiz. -- Kijev : Institut kibernetiki, 1991-. -- ISSN 0023-1274 |
| #643 | Kodai mathematical journal. -- Tokyo : Tokyo Institute of Technology, Department of Mathematics, 1978-. -- ISSN 0386-5991 |
| #644 | Kodai mathematical seminar reports. -- Tokyo : Department of Mathematics. -- ISSN 0023-2599 |
| #645 | Kochi journal of mathematics. -- Kochi : Publication Committee (Mathematics), Faculty of Science, Kochi University, 2006-. -- ISSN 1880-5515 |
| #646 | Kragujevac Journal of Mathematics. -- Kragujevac : Prirodno-matematički fakultet, 2000-. -- ISSN 1450-9628 |
| #647 | Kumamoto journal Of mathematics, A, Matematics. -- Kumamoto : Kumamoto University, Department of Mathematics, Faculty of Science, 1988-. -- ISSN 0914-675X |
| #648 | Kumamoto journal of science, Series A, Mathematics, physics and chemistry. -- Kumamoto : Kumamoto Daigaku Rigakubu, 1952-1969. -- ISSN 0023-5318 |
| #649 | Kumamoto journal Of science. Mathematics. -- Kumamoto : Universtiy of Kumamoto, 1972-1987. -- ISSN 0385-6763 |
| #650 | Kvaternion : časopis o matematice pro aplikace. -- Brno : Ústav matematiky FSI VUT v Brně, 2012-. -- ISSN 1805-1324 |