| #221 | Commentarii mathematici Helvetici. -- Basel : Birkhäuser, 1929-. -- ISSN 0010-2571 print. -- ISSN 1420-8946 online |
| #222 | Commentarii Mathematici Universitatis Sancti Pauli. -- Tokyo : Institute of Mathematics, 1952-. -- ISSN 0010-258X |
| #223 | Commentationes Mathematicae Universitatis Carolinae. -- Prague : Charles University, 1960-. -- ISSN 0010-2628 print. -- ISSN 1213-7243 online |
| #224 | Commentationes physico-mathematicae. -- Helsinki : Society Scientiarum Fennica, 1922-1994. -- ISSN 0069-6609 |
| #225 | Communications Faculty of Sciences University of Ankara, Series A1: mathematics and statistics. -- Ankara : University of Ankara, 1985-. -- ISSN 1303-5991 |
| #226 | Communications in applied numerical methods. -- Chichester : Wiley, 1985-1992. -- ISSN 0748-8025 print. -- ISSN 1555-2047 online |
| #227 | Communications in Mathematical Physics. -- Heidelberg : Springer, 1965-. -- ISSN 0010-3616 |
| #228 | Communications in Mathematics. -- Ostrava : The University of Ostrava, 2010-. -- ISSN 1804-1388 |
| #229 | Communications In partial differential equations. -- New York : Dekker, 1976-. -- ISSN 0360-5302 print. -- ISSN 1532-4133 online |
| #230 | Communications in statistics, Theory and methods. -- New York : Dekker, 1976-. -- ISSN 0361-0926 print. -- ISSN 1532-415X online |