by Ernest O. Lawrence ... [et al.] ; foreword by Harlow Shapley ; edited by George A. Baitsell ; 1st ser - 16th ser. -- Yale University Press, c1939-. -- (The society of the sigma XI : devoted to the encouragement of research in science . National lectureships ; 1937-1938, 1939-1940, 1941-1942, 1943-1944, 1945-1946, 1947-1948, 1949-1950, 1951-1952, 1957-1958, 1959-1960, 1962-1963, 1964-1966).