Letter from Sir Henry Dale to Wilder Penfield, December 4, 1959.
Letter from Sir Henry Dale to Wilder Penfield, January 19, 1960.
Letter from Sir Henry Dale to Wilder Penfield, November 3, 1959.
Letter from the Secretary to Dr. Archibald, Ms. Pickels, to Wilder Penfield, March 20, 1928.
Letter from the Secretary to Dr. Penfield to Charles F. Martin, June 17, 1931.
Letter from Theodore H. Weisenburg to Wilder Penfield, February 20, 1934.
Letter from Theodore Rasmussen to Bernard Berelson, August 31, 1955.
Letter from Theodore Rasmussen to Bernard Berelson, December 20, 1955.
Letter from Theodore Rasmussen to D.L. Thomson, August 24, 1955.
Letter from Theodore Rasmussen to The Ford Foundation, June 25, 1955.
Letter from W.W. Francis to Wilder Penfield, March 27, 1934.
Letter from Walther Spielmeyer to Wilder Penfield, September 14, 1934.
Letter from Ward J. MacNeal to Wilder Penfield, February 14, 1935.
Letter from Ward J. MacNeal to Wilder Penfield, January 22, 1935.
Letter from WGP to Charles Martin, February 24, 1928.