- Poroshin 1952
- O nakhozhdenii Spirialis v Meoticheskikh otlozheniyakh. Doklady Akademii Nauk S.S.S.R. (ns)83(4): 607, 1 fig.
- Van Donk 1977
- O18 as a tool for micropalaeontologists. In: Ramsay, A.T.S. (ed). Oceanic micropalaeontology 1. Acad. Press, London, New York and San Fransisco: 1345-1370.
- Sarnthein 1971
- Oberflächensedimente in Persischem Golf und Golf von Oman, 2. Quantitative Komponentenanalyse der Grobfraktion 'Meteor' Forschungsergebnisse C5: 1-113.
- Dadon 1984b
- Observaciones sobre dos formas de Limacina helicina (Mollusca, Pteropoda)[Obesrevations on two formae of Limacina helicina (Mollusca, Pteropoda) Physis (Buenos Aires)(A) 42(102): 10, 15.
- , 1955
- Observations biologiques effectuées au large de Toulon avec le bathyscaphe F. N. R. S. III de la Marine National. Bull. Inst. Océanogr. Monaco 1061: 1-8.
- Thiriot-Quievreux 1973a
- Observations de la radula des hétéropodes (mollusques, Prosobranchia) au microscope électronique a balayage et interprétation fonctionelle. C. R. Acad. Sci. Paris 276(D): 761-764, 1 pl.
- Bebbington 1986
- Observations on a collection of Glaucus atlanticus (Gastropoda, Opisthobranchia). Haliotis 15: 73-81.
- , McFarlain 1967
- ObserVations on a collection of Glaucus from the Gulf of Aden with critical review of published records of Glaucidae (Gastropoda, Opisthobranchia). Proc. Linn. Soc. London 178(2): 107-123.
- , 1970
- Observations on Australian Glaucidae (Mollusca: Opisthobrnachia). Zool. J. Linn. Soc. 49: 187-197.
- Mörch 1858
- Observations on conchological nomenclature. Ann. Mag. Nat. Hist (3)2: 181-193.
- , Bebbington 1992
- Observations on swimming in pteropods: a reply to Harbison and Gilmer. J. Moll. Stud. 58: 340.
- Harbison 1992
- Observations on the swimming and buoyancy of Cymbulia peroni (Gastropoda: Thecosomata) made from a submersible. J. Mar. Biol. Assoc. U.K. 72: 435-446.
- , Bebbington 1990
- Observations on the swimming and buoyancy of some thecosomatous pteropod gastropods. J. Moll. Stud. 56: 487-497.
- Rang 1827c
- Observations sur le genre Atlante. Mém. Soc. Hist. nat. Paris 3: 372-381, pl. 9.
- Thiriot-Quievreux 1975
- Observations sur les larves et les adultes de Carinariidae (Mollusca, Heteropoda) de l'Océan Atlantique Nord. Mar. Biol. 32: 379-388.
- , 1827a
- Observations zoologiques faites á bord de l'Astrolabe, en mai 1826, dans le détroit de Gibraltar (suite et fin). Description des genres biphore, carinaire, hyale, fläche, cléodore, anatife et briarée. Ann. Sci. Nat. 10: 225-239, (atlas) pls 7-8.
- Winkelmann 1855
- Occurrence of Hyalea off New Zealand. N.Z. J. Sci. 2: 484.
- McGowan 1971
- Oceanic biogeography of the Pacific. In: Funnell, B. M. and Riedel, W. R. (eds). The micropaleontology of oceans. London (Cambridge University Press): 3-74.
- , Deväze 1963
- Océanographie biologique et marine 2. La vie pélagique. Paris (Press Univ. France): 511 pp.
- Forti-Esteves 1985
- Ocorrància de pteropodos na plataforma continental e talude no sul do Brasil. Acta Geologica Leopoldensia 9(20): 5-14, 5 figs.
- Cadée 1961
- Oligocene mollusken van De Vlijt. In: G. [C.] Cadée, M. [C.] Cadée and M. van den Bosch. Fossielen van De Vlijt. Den Haag (Geologiekader D6-12. Nederlandse Jeugdbond voor Natuurstudie): 1-34, 4 pls.
- Brøgger 1901
- Om de senglaciale og postglaciale nivöforandringer i Kristianiafeltet (Molluskfaunan). Norges geol. Undersøgelse 31: i-xi, 1-731, 69 figs, 19 pls.
- Bárdarson 1920
- Om den marine Molluskfauna ved Vestkysten of Island. Kgl. Danske Vid. Selsk. Biol. Meddr. 2(3): 1-139, 1 map.
- Troedsson 1919
- Om Skänes Brachiopodskiffer. Lund Universitetets èrsskrift, (ns)(2)15(3). Or: Kungl. Fysiografiska Sällskapers i Lund Handl. (ns)30(3): 1-110, 2 pls.
- Marrat 1868
- On a collection of pteropods and heteropods. Ann. Mag. Nat. Hist (4)2: 229.
- Godwin-Austen 1882
- On a fossil species of Camptoceras, a freshwater mollusk from the Eocene of Sheerness-on-Sea. Quart. J. Geol. Soc. London 38: 218-221, pl. 5.
- Störmer 1925
- On a Lower Cambian fauna at Untaoset in Norway Helsingfors: 12-22.
- Nayar 1962
- On a new heteropod from the Bay of Bengal. Proc. Rajasthan Acad. Sci. 9(2): 56-57, 1 pl.
- Okutani 1955b
- On a new species of Carinaria, C. japonica. Venus 18(4): 251-258, 3 figs.
- Naomi 1988
- On a swarm of Creseis acicula Rang (Pteropoda) in the Karwar waters. Indian J. Fish. 35(1): 64-65.
- Hilgersom 1984
- On Diacria trispinosa west of Cape Blanc. Plankton Newsl. 1: 3-5.
- Knocker 1868
- On pelagic shells collected during a voyage from Vancouver Island to this country. Proc. Sci. Meet. Zool. Soc. London (
- Okutani 1957b
- On pterotrachean fauna in Japanese waters. Bull. Tokai. Reg. Fish. Res. Lab. 15: 15-21.
- Tokioka 1955a
- On some plankton animals collected by the Syunkotu-Maru in May-June 1954, 2. Shells of Atlantidae (Heteropoda) . Publ. Seto mar. biol. Lab. 4(2-3): 227-235, 5 figs, pls 15-16.
- Tokioka 1955c
- On some plankton animals collected by the Syunkotu-Maru in May-June 1954, 4. Thecosomatous pteropods. Publ. Seto mar. biol. Lab. 5(1): 59-74, pls 7-13.
- Moseley 1877
- On Stylochus pelagicus, and on the larval form of a gymnosomatous pteropod. Quart. J. microsc. Soc. (2)17: 32-34, figs 14-16.
- Sakthivel 1968
- On the abundant occurrence of Desmopterus gardineri Tesch, 1910 (Thecosomata, Mollusca) in the Indian Ocean. J. Bombay Nat. Hist. Soc. 65(1): 259-260.
- Colebrook 1965
- On the analysis of variation in the plankton, the environment and the fisheries. Spec. Publ. int. Comm. N. W. Atl. Fish. 6: 291-302.
- Rattray 1871
- On the anatomy, physiology and distribution of the Firolidae. Trans. Linn. Soc. 27: 255-275, pls 43-44.
- Ranson 1884
- On the cardiac rhytHm of Invertebrata. J. Physiol. London 5: 261-341.
- Mironov 1977
- On the composition of the stomach contents in the young stages of Thecosomata (Mollusca, Pteropoda) from the tropical ocean areas. Biologiya Morya, Kiev 42: 33-39. [in Russian]
- , 1893
- On the dates of the 'Encyclopédie Méthodique' (zoology). Proc. Gen. Meet. sci. bus. zool. Soc. London (
- , 1899
- On the dates of the 'Encyclopédie Méthodique'. Additional note. Proc. Gen. Meet. sci. bus. zool. Soc. London (
- Dall 1889b
- On the genus Corolla Dall. Nautilus 3: 30-32.
- Vyshkvartsev, Sorokin 1978
- On the intensity of assimilation of solvable organic matter by some marine invertebrates. Nauchnye Soob. Inst. biol. Morya Vladivostok 3: 27-31. [in Russian]
- Minichev 1976
- On the morphology of pelagic mollusca Pneumoderatidae (Opisthobranchia, Gymnosomata) from Antarctic waters. Expl. fauna. seas XVIII (XXVI): 102-106.
- Báldi 1969
- On the Oligocene and Miocene stages of the Central Paratethys and on the formations of the Egerian in Hungary. Ann. Univ. Sci. Budap. Rolando Eötvös nom. (sec. geol.) 12 (1968): 19-28, 1 fig.
- Murano 1964
- On the plankton collected on the second Antarctic Ocean research by the Umitaka Maru, 33. The Ocean Research Inst. Univ. Tokyo, 3 (coll. reprints, 1965): 117-134, 1 tab., 8 figs.
- Price 1985
- On the pteropod pavement of the eastern Rio Grande rise. Mar. Geol. 64: 217-235, 5 tabs, 8 figs.
- Mileikovsky 1960
- On the relation between temperature spawning range of a species and its zoogeographical belonging in marine invertebrates. Zool. Zhurn. 39: 666-669. [in Russian]
- Gabb 1873b
- On the topography and geology of Santo Domingo. Trans. Amer. philos. Soc. (ns)15(1): 49-259, 2 maps.
- Furuhashi 1953
- On the vertical distribution of animal plankton in the Sea of Japan off San'in District in summer of 1952. Publ. Seto Mar. Biol. Lab. 3(1): 61-74, 4 figs.
- Kusmorskaya 1950
- On the zooplankton of the Black Sea. Trudy Azovsko-Chernomorsk. Inst. Morsk-Rybn. Khoz. Okeanogr. 14: 177.
- Bogorov, 1955
- On the zooplankton of the north-western Pacific [in Russian]. C. R. Acad. Sci. U.S.S.R. 102(9): 835-838, 2 figs.
- Ganapati, Subba Rao 1957
- On upwelling and productivity of the waters off Lawson's Bay, Waltair. Curr. Sci. 26: 347-348.
- Pelseneer 1892f
- Opercule des hétéropodes. Bull. Soc. malac. Belg. 35: 19-21.
- Wirz-Mangold, Wyrs 1958
- Opisthobranches. Faune des Pyrénées-orientales. Vie et Milieu 9(2): 1-71.
- Barash, Danin 1971a
- Opisthobranchia (Mollusca) from the Mediterranean waters of Israel. Israel J. Zool. 20 (First Ann. Symp. Israel Malac. Soc.): 151-200, 3 tabs, 3 pls, 2 maps.
- Minichev 1972
- Opisthobranchiate molluscs of the Davis Sea. Invest, mar. fauna, 11(9). Res. biol. invest. Sov. Antarct. Exp. 5: 358-382, 10 figs. [in Russian]
- Thiriot-Quievreux 1969b
- Organogénèse larvaire du genre Atlanta (mollusque hétéropode). Vie et Milieu (A)(biol. mar.) 20(2): 347-396, 9 pls.
- Bogorov, 1956
- Osnovnyecherty raspredelenija zooplanktona v severozapadnoj chasti Tikhogo Okeana. Akad. Nauk S.S.S.R. Trudy, Inst. Okeanol. 18: 113-123.
- Pchelintsev, Korobkov 1960
- Osnovy paleontologii. Spravochnik dlya paleontologov i geologov S.S.S.R. Molljuski-Bryukhonogie. (Podotryad Pteropoda). Moskva (Gosudarstv. Nauchno-Tekhn. Izdat. Liter. Geol. Okhrane Nedr.): 251-252, figs 707-711.
- Coppa, Crovato 1985
- Osservazioni biostratigrafiche e paleoecologiche suidepositi argillosi emiliani e siciliani di Gallipoli (Puglia). Boll. Soc. Natur. Napoli 92(1983): 159-225, 4 tabs, 4 figs, 10 pls.
- Buccheri 1985
- Osservazioni paleoclimatiche al limite Pleistocene inferiore-Pleistocene medio della foce del Belice (Sicilia sud-occidentale) mediante l'uso degli pteropodi. Boll. Soc. Geol. Ital. 104: 115-122, 3 figs.
- Buccheri 1983
- Osservazioni paleoclimatiche sul Siciliano della Sicilia occidentale. La sezione della località tipo di Ficarazzi (Palermo). Rend. Soc. Geol. Ital. 5(1): 51-54, 1 fig.
- Vitagliano 1950
- Osservazioni sul compartamento delle cellule follicolari nelle gametogenesi di Cavolinia tridentata Forskäl (Moll. Pterop.). Pubbl. Staz. Zool. Napoli 22: 367-377, pls 11-12.
- Capuis, Ciaccio 1947
- Osservazioni sulla gametogenesi di Cavolinia tridentata. Arch. zool. Torino 3: 57-64.
- Vitagliano, Bacci 1951
- Osservazioni sulla spermaogenesi degli pteropodi. Sci. Genet. 4(1-2): 30-35, 2 figs.
- , 1985
- Oxygen uptake and buoyancy in zooplankton organisms from the tropical Atlantic. Comp. Biochem. (A)81 (4): 857-863.