Ogilby J. D., 1911: Descriptions of new or insufficiently described fishes from Queensland waters. 24 pp.
 
ZME 78249
Oijen M. J. P. van, 2004: Haplochromis ushindi spec. nov., the largest piscivorous cichlid in the Mwanza Gulf area of Lake Victoria (East Africa) before the Nile perch upsurge. 6 pp. Zoologische Mededelingen Leiden 78: 249-255.
 
ZME 82167
Oijen M. J. P. van, Zeeuw M. P. de, 2008: Haplochromis vonlinnei spec. nov., a piscivorous haplochromine cichlid (Teleostei, Perciformes) from the Mwanza Gulf area of Lake Victoria. 9 pp. Zoologische Mededelingen 82: 167-175.
 
ZME 66561
Oijen, 1992: Haplochromis howesi spec. nov., a crab and fish eating cichlid from Lake Victoria. 19 pp. [81177] Zoologische Mededelingen 66(40): 561-579.
 
PSC 218
Oliveira E. C., Ferreira E. J. G., 2002: Occurence of eggs and larvae of migratory Characiformes fish in the Negro River, Amazonas State, Brazil. 6 pp. Acta Amazonica 32(1): 163-168.
 
PSC 71
Orsi M. L., Shibatta O. A., 1999: Crescimento de Schizodon Intermedius Garavello Britski (Ostheichthyes, Anostomidae) do Rio Tibagi (Sertanópolis, Paraná). 10 pp. Revta bras. Zool. 16(3): 701-710.
 
SPX 32153
Ottoni F. P., Cheffe M. M., 2009: A new species of Australoheros from the upper rio das Antas, laguna dos Patos System, southern Brazil (Labroidei, Cichlidae, Chichlasomatinae). 7 pp. Spixiana 32(1): 153-159.