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- Letterman General Hospital (San Francisco, Calif.), author.1
- Lewis, William, 1708-17815
- Lloyd, John Uri, 1849-19362
- Lord, Owen & Co.1
- M. S. (Moses Stringer)1
- MacKenzie, Colin, 1775?-18271
- Magendie, François, 1783-18553
- Massachusetts College of Pharmacy, author.1
- Massachusetts Medical Society.1
- Mayne, John.1
- McKesson and Robbins, Inc.7
- Medical Society of the State of New York (1807- )1
- Merck & Co.1
- Merrick, Billings & Otis.1
- Merrick, Otis & Co.1
- Mildred & Allen.1
- Millennial World Congress of Pharmaceutical Sciences (2000 : San Francisco, Calif.)1
- Mitchell, Charles L., author1
- Mitchell, Thomas D. (Thomas Duché), 1791-18651