Obata I., Futakami M., Suzuki T., 1991: Eubostrychoceras densicostatum Matsumoto, a large Heteromorph ammonite species, from the Upper Cretaceous of Wakkanai in Hokkaido. 7 pp. Memoirs of the National Science Museum 24: 27-33.
 
HNR 76
Obata I., Kubodera T., Shinohara A., Tanaka J., Hagiwara H., Yokoyama K., Tomida Y., Mizoguchi Y., 1991: Preface to the Natural History Researches of northern Hokkaido. 5 pp. (in Japanese). Memoirs of the National Science Museum 24: 1-5.
 
ASC 27112
Obenberger J., 1930: Nové kompendium lékařské entomologie. 3 pp. [INS 363] Acta Societatis entomologicae Cechosloveniae 27: 112-114.
 
BIO 79
Obenberger J., Ogloblin A. A., : G. G. Jakobson. 3 pp.
 
GLG 89
Ohguchi T., Tiba T., 1987: Neogene volcanism in the northern Honshu, Japan. Part 1. Historical change of volcanic fields. 11 pp. (in Japanese). Memoirs of the National Science Museum 20: 15-25 pp.
 
GLG 90
Ohguchi T., Tiba T., 1987: Neogene volcanism in the northern Honshu, Japan. Part 2. Mode of occurrences of volcanic rocks along the north coast of the Tsugaru Peninsula. 9 pp. (in Japanese). Memoirs of the National Science Museum 20: 27-35.
 
TRV 115
Ohlin A., 1898: A zoologist in Tierra del Fuego: some account of the Swedish expedition, 1895-96. 10 pp. (in English). Natural Science 9(55): 172-181.
 
95283
Ohly J., 1985: Die Wasserbüffelwirtschaft am mittleren Amazonas aus der Sicht der jüngsten Entwicklungen. 17 pp. Amazoniana 9(3): 441-457.
 
ZME 804001
Oijen M. J. P. van, Ligny W. de, 2006: Marinus Boeseman, 1916-2006, a biography and a list of his publications. 8 pp. Zoologische Mededelingen Leiden 80(4): 1-8.
 
95521
Oka A., 1922: A criticism on the present civilization. 26 pp. (in English).
 
MUZ 36
Okáli I., 1983: Činnos Slovenskej entomologickej spoločnosti pri SAV v rokoch 1977 a 1982. 12 pp.
 
95134
Okazawa T., 1975: Aquatic insect survey of the river Kaunnai, with special reference to the Rockey Chute Bed fauna. 16 pp. Kontyu, Tokyo 43(4): 497-512.
 
95522
Oldekop E., 1930: Über das Hierarchische Prinzip in der Natur und seine Beziehungen zum Mechanismus-Vitalismus-Problem. 64 pp. (in German).
 
REP 175
Olexa A., 1962: Über die Haltung des Bunten Zwergchamäleons Microsaurus pumilus Daud. 9 pp. (in German). [M52] Aquarien und Terrarien: 33-41.
 
AGR 52
Oliveira A. N., Oliveira L. A., Figueiredo A. F., 2003: Arbuscular mycorrhizal colonization and nutrient concentration of three cultivars of banana on a Central Amazonian Oxisol. 8 pp. Acta Amazonica 33(3): 345-352.
 
BIO 146
Olson C. A., 1994: Floyd Gerald Werner 1921-1992. 12 pp. (in English). Psyche 101(1-2): 1-12.
 
WLC 21
Oordt G. J. van, 1935: De staatsnatuurreservaten. 8 pp. (in Dutch).
 
95523
Origonis P., 1843: Von der Erzeugung und ihren Theorien. 20 pp. (in German).
 
GLG 95
Örkényi-Bondor L., 1974: The plagioclase crystals of the andesite agglomerate from Csattogó Hill in Börzsöny Mountains (Hungary). 18 pp. Ann. Hist.-nat. Mus. Nat. Hung. 66: 5-22.
 
95327
Ortiz-Sánchez F. J., 2007: Charles Duncan Michener (1918-), una larga vida dedicada a la Entomología (I). Biografía y publicaciones. 47 pp. (in Spanish). Boletin de la Asociación espanola de Entomología 31(1-2): 17-63.
 
EFA 1534
Ortiz-Sánchez F. J., Tinaut A., 1994: Efecto de la polinazición mediante insectos sobre la producción en una variedad híbrida de girasol (Helianthus annus L.) en el sur de Espana. 8 pp. [M23] Entomofauna 15/34.
 
8370
Ouchi Y., 1936: 1935 supplements to Bibliographical introduction to the study of Chinese insects. 96 pp.
 
95138
Ozereckovskaya N. G., Smirnova N. F., 1959: Gidrochimičeskie issledovania r. Psekups i prudov Krasnodarskogo kraja v svjazi s udobreniem. 33 pp.