| #2691 | Optometry - Journal of the American Optometric Association. -- St. Louis : Elsevier, 2000-. -- ISSN 1529-1839 print. -- ISSN 1558-1527 online |
| #2692 | Optotyp. -- Bratislava : Robin Look, 1993-1996. -- ISSN 1335-0110 |
| #2693 | Oral and maxillofacial surgery. -- Berlin : Springer, 2008-. -- ISSN 1865-1550 print. -- ISSN 1865-1569 online |
| #2694 | Oral diseases. -- Oxford : Blackwell, 1995-. -- ISSN 1354-523X print. -- ISSN 1601-0825 online |
| #2695 | Oral microbiology and immunology. -- Copenhagen : Blackwell, 1986-2009. -- ISSN 0902-0055 print. -- ISSN 1399-302X online |
| #2696 | Oral Oncology Extra. -- : Pergamon. -- ISSN 1741-9409 |
| #2697 | Oral oncology. Supplement. -- Amsterdam : Elsevier, 2005-. -- ISSN 1744-7895 |
| #2698 | Oral radiology. -- Tokyo : Springer, 1985-. -- ISSN 0911-6028 print. -- ISSN 1613-9674 online |
| #2699 | Oral surgery, oral medicine, oral pathology and oral radiology. -- New York : Elsevier, 2012-. -- ISSN 2212-4403 print. -- ISSN 2212-4411 online |
| #2700 | Oral surgery, oral medicine, oral pathology, oral radiology and endodontics. -- St. Louis : Mosby, 1995-. -- ISSN 1079-2104 |