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- Andrews, Edmund, 1824-19041
- Andrews, Joseph A. (Joseph Alfred), 1858-19281
- Aragón, José M., author1
- Arratia, Aurelio, author1
- Ashby, Henry, 1845-19081
- Ashhurst, John, 1839-19001
- Ashmead, Albert S., author1
- Ashton, William Easterly, 1859-1933, author1
- Association of Hospital Physicians and Surgeons of Philadelphia, compiler.1
- Atkins, Francis Higginson, 1843-, author1
- Atkinson, Edward, 1827-1905, author1
- Axtell, E. R. (Edwin Rodarmel), 1866-1899, author1
- Ayres, Douglas, author1
- Babcock, Stephen E. (Stephen Eldredge), author1
- Baer, B. F. (Benjamin Franklin), 1846-19202
- Baker, Albert Rufus, 1858- author1
- Baker, Frank, 1841-19181
- Balch, Lewis, 1847-19091
- Baldy, J. M. (John Montgomery), 1860-19342