Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1974)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1976)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1977)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1980)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1981)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1989)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1990)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1991)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1992)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1993)

Occasional papers of the Museum of Natural History, the University of Kansas - University of Kansas. Museum of Natural History. (The University, 1994)

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Occasional papers of the Museum of Zoology, University of Michigan - University of Michigan. Museum of Zoology. (University of Michigan, 1915)

Occasional papers of the Museum of Zoology, University of Michigan - University of Michigan. Museum of Zoology. (University of Michigan, 1913)

Occasional papers of the Museum of Zoology, University of Michigan - University of Michigan. Museum of Zoology. (University of Michigan, 1917)

Occasional papers of the Museum of Zoology, University of Michigan - University of Michigan. Museum of Zoology. (University of Michigan, 1918)

Occasional papers of the Museum of Zoology, University of Michigan - University of Michigan. Museum of Zoology. (University of Michigan, 1923)

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Odontographie. Vergleichende Darstellung des Zahnsystemes der lebenden und fossilen Wirbelthiere - Giebel, C. (Christoph), 1820 -1881 (A. Abel, 1855)

Odontography : or a treatise on the comparative anatomy of the teeth, their physiological relations, mode of development and microscopic structure, in the vertebrate animals - Owen, Richard, 1804 -1892 (Hippolyte Bailliere, 1840)

Odontography; or, A treatise on the comparative anatomy of the teeth; their physiological relations, mode of development, and microscopic structure, in the vertebrate animals - Owen, Richard, 1804 -1892 (H. Baillière, 1840)

Oesterreichische botanische Zeitschrift (A. Skofitz, 1908)

Oeuvres du comte de Lacépède : comprenant l'histoire naturelle des quadrupèdes ovipares, des serpents, des poissons et des cétacés; accompanées du portrait de l'auteur et d'environ 400 figures, exécutés pour cette édition par les meilleurs artistes - Cuvier, Georges, baron, 1769 -1832 (Chez F.D. Pillot, 1832)

Official lists and indexes of names and works in zoology. Supplement 1986-2000 - International Commission on Zoological Nomenclature (International Trust for Zoological Nomenclature, c/o Natural History Museum, 2001)

Official lists and indexes of names and works in zoology - International Commission on Zoological Nomenclature (ICZN, 1987)

Öfversigt af Kongl. Vetenskaps-akademiens forhandlingar - Kungl. Svenska vetenskapsakademien. (P. A. Norstedt & Söner, 1854)

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The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1907)

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Okens Lehrbuch der Naturgeschichte - Oken, Lorenz, 1779 -1851 (Bei Carl Heinrich Reclam, 1813)

Okens Lehrbuch der Naturgeschichte - Oken, Lorenz, 1779 -1851 (Bei Carl Heinrich Reclam, 1816)

Old bones : or, Notes for young naturalists - Brooks, Vincent, 1815? -1885 (Robert Hardwicke, 1861)

On the anatomy of vertebrates - Owen, Richard, 1804 -1892 (Longmans, Green, 1866)

On the anatomy of vertebrates ... - Owen, Richard, 1804 -1892 (Longmans, Green and Co, 1866)

On the batrachia and reptilia of Costa Rica : With notes on the herpetology and ichthyology of Nicaragua and Peru - Cope, E. D. (Edward Drinker), 1840 -1897 (s.n, 1875)

On the batrachia and reptilia of Costa Rica : With notes on the herpetology and ichthyology of Nicaragua and Peru / by E. D. Cope - Cope, E. D. (Edward Drinker), 1840 -1897 (s.n, 1875)