Les oiseaux du Canada - Dionne, C.-E. (Charles-Eusèbe), 1846 -1925 (P. G. Delisle, 1883)

Les oiseaux - Perrier, Edmond, 1844 -1921 (J.B. Bailli, 1904)

Oiseaux - Fédération des sociétés françaises de sciences naturelles. Office central de faunistique. (P. Lechevalier, 1921)

Olavi Rudbeck filii Dudaim rubenis : quos neutiquam Mandragorae, fructus fuisse, aut flores amabiles, Lilia, Violas, Narcissos, Leucoja, species Melonis, Vaccinia, Chamaebatum, Rosam, Solanum halicacabum, certas Uvas, Tubera, Maiisch, Circaeam, Hordeum, Philtra amatoria &c. Sed fraga vel mora Rubi idaei spinosi, allatae hic rationes satis videntur evincere - Rudbeck, Olof, 1660 -1740 (Literis Wernianis, 1733)

Oldman River Dam ... raptor mitigation program - Alberta. Alberta Environment. (Govt. of the Province of Alberta, Dept. of Public Works, Supply and Services, 1992)

Om lydorganer hos fiske : En physiologisk og comparativanatomisk undersøgelse - Sørensen, William, 1848 -1916 (V. Thaning & Appels boghandel, trykt hos J.H. Schultz, 1884)

On a collection of birds from North-Eastern Abyssinia and the Bogos Country - Jesse, William. (Zoological Society of London, 1870)

On agriculture, with a recension of the text and an English translation by Harrison Boyd Ash - Columella, Lucius Junius Moderatus. (Harvard University Press, 1941)

On animal and vegetable parasites of the human body, a manual of their natural history, diagnosis, and treatment - Küchenmeister, Friedrich, 1821 -1890 (Printed for the Sydenham Society, 1857)

On farming : M. Terenti Varronis Rerum rusticarum libri tres - Storr-Best, Lloyd, (G. Bell, 1912)

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 habits and instincts of animals - Swainson, William, 1789 -1855 (Printed for Longman, Orme, Brown, Green, & Longmans, 1840)

On the natural history and classification of birds - Swainson, William, 1789 -1855 (John Taylor, 1836)

On the Natural History and classification of Birds : vol. I and II - Swainson, William, 1789 -1855 (pr. for Longman [etc.], 1836)

On the power, wisdom and goodness of God, as manifested in the creation of animals, and in their history, habits and instincts - Kirby, William, 1759 -1850 (Carey, Lea & Blanchard, 1836)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1904)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1905)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1911)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1913)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1918)

The oölogist's record (Harrison and Sons, 1923)

Oologia neerlandica : eggs of birds breeding in the Netherlands - Lechner, Arnold Anthon van Pelt (Nijhoff, 1911)

Ootheca Wolleyana: an illustrated catalogue of the collection of birds' eggs - Newton, Alfred, 1829 -1907 (sold by R. H. Porter, 1864)

Ootheca Wolleyana: an illustrated catalogue of the collection of birds' eggs - Newton, Alfred, 1829 -1907 (sold by R. H. Porter, 1907)

Opera ornithologica - Bonaparte, Charles-Lucien, 1803 -1857 (1857)

Opera posthuma :figuris aeneis illustrata, quibus praefixa est ejusdem vita a seipso scripta - Malpighi, Marcello, 1628 -1694 (Churchill, 1697)

Opuscula medica, quae reperiri potuere omnia, nunc primo simul edita - Drelincourt, Charles, 1633 -1697 (Apud Alberts & van der Kloot, 1727)

Opuscula ornithologica : notis et addendis, mss - Coues, Elliott, 1842 -1899 (1861)

Orang-outang, sive homo sylvestris: or, The anatomy of a pygmie compared with that of a monkey, an ape, and a man. To which is added, A philological essay concerning the pygmies, the cynocephali, the satyrs, and sphinges of the ancients. Wherein it will appear that they are all either apes or monkeys, and not men, as formerly pretended - Tyson, Edward, 1650 -1708 (Printed for T. Bennett and D. Brown, and are to be had of Mr. Hunt, 1699)

The Orchid world. A monthly illustrated journal entirely devoted to orchidology - Wilson, Gurney, 1878 - (Alabaster, Passmore & Sons, ltd., printers], 1914)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1885)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1886)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1887)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1888)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1889)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1890)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1891)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1895)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1898)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1899)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1901)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1903)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1904)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1910)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1905)