Ruiz, Dr. Adrian (1956, 1 letter) Ryckman, Raymond E. (undated, 1 letter) Ryerson, Knowles A. (1932–1954, 16 letters) Sage, Mrs. (1952, 1 letter) Saint, Abel (1948–1957, 29 letters) Salazar P., Guillermo (1949–1952, 17 letters) Salomon, Dr. Hugo (1948–1950, 3 letters) Samper, Jaime (1951, 1 letter) Sand, Dr. Seaward A. (1955, 3 letters) Sax, Dr. Karl (1949, 3 letters) Sayago, Dr. Marcelino (1948, 1 letter) Scasso, Juan A. (1950, 1 letter) Schieck, Robert N. (1951–1952, 10 letters) Schoenfeld, William J. (1949–1950, 5 letters)