Letter from Wilder Penfield to Alfred Stengel, November 30, 1931.
Letter from Wilder Penfield to Archibald Malloch, November 9, 1934.
Letter from Wilder Penfield to Arthur Childe, January 23, 1940.
Letter from Wilder Penfield to Arthur E. Childe, January 10, 1941.
Letter from Wilder Penfield to Athanase David, September 18, 1934.
Letter from Wilder Penfield to Barnet Phillips, March 1, 1934.
Letter from Wilder Penfield to Barnet Phillips, March 16, 1934.
Letter from Wilder Penfield to Barnet Phillips, March 28, 1934.
Letter from Wilder Penfield to Bernardus Brouwer, November 9, 1934.
Letter from Wilder Penfield to Bill Stewart, July 31, 1940.
Letter from Wilder Penfield to Bill Stewart, September 16, 1940.
Letter from Wilder Penfield to Boris Babkin, March 27, 1940.
Letter from Wilder Penfield to Boris Babkin, May 25, 1933.
Letter from Wilder Penfield to Brooke Claxton, December 18, 1946.
Letter from Wilder Penfield to C. Tom Crocker, March 6, 1971.