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- Ohmann-Dumesnil, A. H. (Amant Henry), 1857-1919 author36
- Okie, A. Howard (Abraham Howard)1
- Olaguíbel, Manuel de, 1845-1900, author1
- Old Smoker, 1822-1891, author1
- Oldberg, Oscar, 1846-19131
- Oldberg, Oscar, 1846-1913, author3
- Oldshue, L. (Lincoln), 1820-18861
- Oliva, Leonardo, 1814-18721
- Oliva, Leonardo, 1814-1872, author1
- Olivares, Ambrosio R.1
- Oliveira, Manoel Bastos de.1
- Oliveira, Oscar Sergio Rodrigues de.1
- Oliveira, Pedro Ernesto Albuquerque de.1
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- Oliver, Charles A. (Charles Augustus), 1853-1911 author26
- Oliver, Charles A. (Charles Augustus), 1853-1911, author14
- Oliver, F. E. (Fitch Edward), 1819-18921