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- Ochsner, Albert J. (Albert John), 1858-19251
- Oettinger, B. (Bernard), author1
- Ohlemann, F. W. Max, author1
- Oppenheimer, Seymour, 1871-1957, author1
- Osler, William, Sir, 1849-1919, author1
- Ostrom, Kurre W. (Kurre Wilhelm), 1865-1