| #541 | Pollution abstracts with indexes. -- Cambridge : Cambridge Scientific Abstracts, 1970-. -- ISSN 0032-3624 |
| #542 | Pollution engineering. -- Northbrook : Pudvan Pub. Co., 1969-. -- ISSN 0032-3640 print. -- ISSN 1937-4437 online |
| #543 | Population ecology. -- Tokyo : Springer-Verlag Tokyo Inc., 1999-. -- ISSN 1438-3896 print. -- ISSN 1438-390X online |
| #544 | Proceedings - Institute of Wastes Management. -- Northampton : Institute of Wastes Management, 1992-1999. -- ISSN 0968-7068 |
| #545 | Proceedings of the Estonian Academy of Sciences, Biology, ecology. -- Tallin : Estonian academy publishers, 1997-. -- ISSN 1406-0914 |
| #546 | Process safety and environmental protection. -- Rugby : The Institution of Chemical Engineers, 1990-. -- ISSN 0957-5820 print. -- ISSN 1744-3598 online |
| #547 | Progress in oceanography. -- Oxford : Pergamon Press, 1963-. -- ISSN 0079-6611 print. -- ISSN 1873-4472 online |
| #548 | RAC. -- Croydon : Emap Maclaren, 1991-. -- ISSN 1460-9878 |
| #549 | Radiacionnaja biologija radioèkologija. -- Moskva : Nauka, 1993-. -- ISSN 0869-8031 |
| #550 | Radiation and environmental biophysics. -- Berlin : Springer, 1974-. -- ISSN 0301-634X print. -- ISSN 1432-2099 online |