| #991 | Obzornik za matematiko in fiziko. -- Ljubljana : Društvo matematikov, fizikov in astronomov SR Slovenije, 1951-. -- ISSN 0473-7466 |
| #992 | Odborné semináře : sborník za rok ..., roč. ... : Roč. VIII, r. 2008/2009 název pouze v angličtině: Scientific seminars : proceedings from year ... -- Česká Republika : Praha : Československá sekce IEEE, 2003, 2002-2009 |
| #993 | OK QRP Info. -- Praha : OK QRP klub, 1990-. -- ISSN 2336-2014 |
| #994 | Optica Applicata. -- Wroclaw : Technical University, 1971-. -- ISSN 0078-5466 print. -- ISSN 1899-7015 online |
| #995 | Optical and quantum electronics. -- London : Chapmann and Hall, 1975-. -- ISSN 0306-8919 print. -- ISSN 1572-817X online |
| #996 | Optical engineering : the journal of SPIE - the International Society for Optical Engineering. -- Bellingham : Society of Photo-Optical Instrumentation Engineers, 1972-. -- ISSN 0091-3286 |
| #997 | Optical fiber technology. -- San Diego : Academic Press, 1994-. -- ISSN 1068-5200 print. -- ISSN 1095-9912 online |
| #998 | Optical journal and review of optometry. -- Spojené státy americké : Philadelphia : Chilton, 1900-1977. -- ISSN 0030-3925 |
| #999 | Optical memory news. -- San Francisco : Rothchild Consultants, 1983-. -- ISSN 0741-5869 |
| #1000 | Optical networks magazine. -- Bellingham : SPIE-International Society for Optical hamEngineering, 2000-2003. -- ISSN 1388-6916 print. -- ISSN 1572-8161 online |