Oberholser H. C., 1896: Descriptions of two new subspecies of the dowmy woodpecker, Dryobates pubescens (Linnaeus). 4 pp. 

 Oberholser H. C., 1899: A revision of the wrens of the genus Thryomanes Sclater. 30 pp. 

 Oberholser H. C., 1900: A list of the birds collected by Mr. R. P. Currie in Liberia. 14 pp. 

 Oberholser H. C., 1900: Catalogue of a collection of birds from Madagascar. 14 pp. 

 Oberholser H. C., 1900: Notes on birds collected by doctor W. L. Abbott in Central Asia. 24 pp. 

 Oberholser H. C., 1900: Notes on birds from the Cameroons district, West Africa. 9 pp. 

 Oberholser H. C., 1900: Notes on some birds from Santa Barbara Islands, California. 6 pp. 

 Oberholser H. C., 1902: Catalogue of a collection of hummingbirds from Ecuador and Colombia. 34 pp. 

 Oberholser H. C., 1903: List of birds collected by William T. Foster in Paraguay. 21 pp. 

 Oberholser H. C., 1903: Some new South American birds. 10 pp. 

 Oberholser H. C., 1904: A review of the wrens of the genus Troglodytes. 15 pp. 

 Oberholser H. C., 1904: A revision of the American great horned owls. 16 pp. 

 Oberholser H. C., 1904: Descriptions of a new african weaver-bird. 1 pp. 

 Oberholser H. C., 1906: Notes on birds from German and British East Africa. 11 pp. 

 Oberholser H. C., 1909: A revision of the kingfisher genus Ramphalcyon (Pelargopsis). 23 pp. 

 Oberholser H. C., 1911: A monograph of the flycatcher genera Hypothymis and Cyanonympha. 31 pp. 

 Oberholser H. C., 1911: A revision of the forms of the hairy woodpecker Dryobates villosus (Linnaeus). 28 pp. 

 Oberholser H. C., 1913: A revision of the forms of the great blue heron (Ardea herodias Linnaeus). 29 pp. 

 Oberholser H. C., 1915: A review of the subspecies of the ruddy kingfisher, Entomothera coromanda (Linnaeus). 19 pp. 

 Oberholser H. C., 1916: A synopsis of the races of the crested tern, Thalasseus bergii (Lichtenstein). 13 pp. 

 Oberholser H. C., 1916: Critical notes on the subspecies of the spotted owl, strix occidentalis (Xantus). 7 pp. 

 Oberholser H. C., 1917: The birds of Bawean Island, Java Sea. 16 pp. 

 Oberholser H. C., 1919: A review of the subspecies of the leach petrel, Oceanodroma leucorhoa (Vieillot). 8 pp. 

 Oberholser H. C., 1919: Birds collected by Dr. W. L. Abbott on various Islands in the Java Sea. 24 pp. 

 Oberholser H. C., 1920: Notes on the wrens of the genus Nannus Billberg. 14 pp. 

 Oberholser H. C., 1920: The birds of the Tambelan Islands, South China Sea. 15 pp. 

 Oberholser H. C., 1920: The races of the Nicobar megapode, Megapodius nicobariensis Blyth. 4 pp. 

 Oberholser H. C., 1925: Notes on birds collected by Dr. W. L. Abbott on the Karimata Islands, off West Borneo. 4 pp. 

 Obuch J., 1994: Príspevok k pomernému zastúpeniu mikromammálií v Turci. 6 pp. 

 Ogilby J. D., 1911: Descriptions of new or insufficiently described fishes from Queensland waters. 24 pp. 

 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.

 Oijen M. J. P. van, Roselaar C. S., 2007: Notes on types and early specimens of Bombycivora japonica von Siebold, 1824, and of Bombycilla phoenicoptera Temminck, 1828. 8 pp. Zoologische Mededelingen Leiden 81: 251-258.

 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.

 Oijen, 1992: Haplochromis howesi spec. nov., a crab and fish eating cichlid from Lake Victoria. 19 pp. [81177] Zoologische Mededelingen 66(40): 561-579.

 Olexa A., 1962: Über die Haltung des Bunten Zwergchamäleons Microsaurus pumilus Daud. 9 pp. (in German). [M52] Aquarien und Terrarien: 33-41.

 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.

 Olson S. L., Violani C., 1995: Some unusual hybrids of Ramphocelus, with remarks on evolution in the genus (Aves: Thraupinae). 16 pp. 

 Oorschot R. A. H., Cooper D. W., Moore D. S., 1989: The origin of the feral dama (tammar) wallabies Macropus eugenii, in the Rotorua area of New Zealand. 4 pp. 

 Opatrný E., 1970: Biometrické srovnání našich druhů skokanů (Ranidae, Amphibia). 19 pp. 

 Orgeira T. J. L., 1995: Seabird observations of the Argentine Atlantic shore between Tierra del Fuego and Buenos Aires. 11 pp. 

 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.

 Osborn D. J., Krombein K. V., 1969: Habitats, flora, mammals, and wasps of Gebel’Uweinat, Libyan desert. 18 pp. Smithsonian Contributions to Zoology

 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.