Die offizinellen Pflanzen und Drogen :eine systematische Übersicht über die in sämtlichen Staaten Europas sowie in Japan und den Vereinigten Staaten von Amerika offizinellen Pflanzen und Drogen mit kurzen erläuternden Bemerkungen - Mitlacher, Wilhelm, 1872 -1913 (C. Fromme, 1912)

Ohio fossils - La Rocque, Aurèle, 1909 - (Ohio Dept. of Natural Resources, Division of Geological Survey, 1955)

The Ohio journal of science - Ohio Academy of Science. (Ohio Academy of Science, 1909)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1903)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1905)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1909)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1906)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1910)

The Ohio naturalist - Ohio Academy of Science. (Biological Club of the Ohio State University, 1911)

Om algevegetationen ved Faerøernes kyster en plantegeografisk undersøgelse - Børgesen, Frederik, 1866 -1956 (Gyldendalske boghandel, Nordisk forlag, 1904)

On the evolution of the Proboscidea - Andrews, Charles William, 1866 -1924 (1903)

The Ontario natural science bulletin - Wellington Field Naturalists' Club. (Wellington Field Naturalists' Club, 1910)

The Ontario natural science bulletin - Wellington Field Naturalists' Club. (Wellington Field Naturalists' Club, 1905)

The Ontario natural science bulletin - Wellington Field Naturalists' Club. (Wellington Field Naturalists' Club, 1906)

The Ontario natural science bulletin - Wellington Field Naturalists' Club. (Wellington Field Naturalists' Club, 1913)

The Ontario natural science bulletin - Wellington Field Naturalists' Club. (Wellington Field Naturalists' Club, 1912)

Onze flora. Beschrijving van de familiën, voornamste geslachten en soorten der in Nederland in het wild groeiende, verwilderde, verbouwde en aangeplante gewassen, alsmede van eenige fraaie en nuttige midden-europeesche planten - Hoffmann, Carl, 1802 -1883 (W.J. Thieme, 1900)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1895)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1897)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1898)

The Oölogist for the student of birds, their nests and eggs - Lattin, Frank H. (Frank H. Lattin, 1899)

The Orchid review (Orchid Review ltd.], 1923)

Organography of plants, especially of the Archegoniata and Spermaphyta - Balfour, Isaac Bayley, 1853 -1922 (Clarendon press, 1900)

Organography of plants, especially of the archegoniatae and spermaphyta - Goebel, K. (Karl), 1855 -1932 (Clar. Press, 1900)