| #2681 | Operative techniques in otolaryngology-head and neck surgery. -- Philadelphia : W.B. Saunders, 1990-. -- ISSN 1043-1810 print. -- ISSN 1557-9395 online |
| #2682 | Operative techniques in plastic and reconstructive surgery. -- Philadelphia : W.B. Saunders, 1994-2002. -- ISSN 1071-0949 print. -- ISSN 1558-0741 online |
| #2683 | Operative techniques in sports medicine. -- Philadelphia : W.B. Saunders, 1993-. -- ISSN 1060-1872 print. -- ISSN 1557-9794 online |
| #2684 | Operative techniques in thoracic and cardiovascular surgery. -- Philadelphia : W.B. Saunders, 1998-. -- ISSN 1522-2942 print. -- ISSN 1532-8627 online |
| #2685 | Ophthalmic & physiological optics. -- Guilford : Blackwell Scientific, 1981-. -- ISSN 0275-5408 print. -- ISSN 1475-1313 online |
| #2686 | Ophthalmic research. -- Basel : Karger, 1970-. -- ISSN 0030-3747 |
| #2687 | Der Ophthalmologe. -- Berlin : Springer-Verlag, 1992-. -- ISSN 0941-293X print. -- ISSN 1433-0423 online |
| #2688 | Ophthalmologica. -- Basel : Karger, 1938-. -- ISSN 0030-3755 |
| #2689 | Ophthalmology. -- New York : Elsevier Science, 1978-. -- ISSN 0161-6420 print. -- ISSN 1549-4713 online |
| #2690 | Opportunistic pathogens. -- Amsterdam : Elsevier, 1997. -- ISSN 1386-2618 |