| #491 | Notes and records of the Royal Society of London. -- London : Royal Society of London, 1938-. -- ISSN 0035-9149 print. -- ISSN 1743-0178 online |
| #492 | Notulae naturae. -- Philadelphia : Academy of Natural Sciences of Philadelphia, 1939-. -- ISSN 0029-4608 |
| #493 | Nova acta Leopoldina. -- Leipzig : Barth, 1933-. -- ISSN 0369-5034 |
| #494 | Oberrheinische Geologische Abhandlungen. -- Karlsruhe : C. F. Muller, 1929-. -- ISSN 0078-2939 |
| #495 | Occasional papers of the Museum of Natural History. -- Lawrence : University of Kansas, 1994-1996. -- ISSN 0091-7958 |
| #496 | Ocean and shoreline management. -- Barking : Elsevier, 1988-1991. -- ISSN 0951-8312 print. -- ISSN 1872-7816 online |
| #497 | Ocean modelling. -- Oxford : Elsevier, 1999-. -- ISSN 1463-5003 print. -- ISSN 1463-5011 online |
| #498 | Oceanology. -- Moscow : Nauka, 1965-. -- ISSN 0001-4370 |
| #499 | Odyssey. -- Peterborough : Cobblestone Pub., 1992-. -- ISSN 0163-0946 |
| #500 | Oil & chemical pollution. -- Barking : Elsevier, 1986-. -- ISSN 0269-8579 print. -- ISSN 1878-1934 online |