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- Muller, H. J. (Hermann Joseph), 1890-1967, author1
- Muniagurria, Camilo, 1876-1937, author1
- Murray, W. John (William John), author1
- National Association of Chiropodists (U.S.), author.1
- National Health Council (U.S.), author.1
- National Industrial Conference Board, author, issuing body.1
- Neuhof, Harold, 1884- author1
- Neuhof, Selian, 1871- author1
- Noguchi, Hideyo, 1876-1928, author1
- Noyes, Edmund, 1842-1927 author1
- O'Flaherty, Claude, 1878-1955, author1
- O'Shea, M. V. (Michael Vincent), 1866-1932, author1
- Ochsner, Edward H. (Edward Herman), 1868-1956, author1
- Ogle, Clairel L. (Clairel Leroy), Jr., 1893- author1
- Oliphant, H. N. (Homer Newton), 1880-1924 author, publisher1
- Osler, William, Sir, 1849-19191
- Ottofy, Louis, 1860- author1
- Overton, Frank, 1867-1
- Pacini, A. J. (August John), 1888- author1