by University of California. Bureau of Research in Education

1921

by Ohio State University

1923

by Pennsylvania State University. Schoolmen's Week

1928

by Stanford University

1929

by Ohio State University

1923

by University of California, Berkeley

1961

by University of Michigan

1920

by University of Pennsylvania. John Herr Musser Department of Research Medicine

1916

by Columbia University. Teachers College

1925

by University of Minnesota

1923

by Stanford University Stanford Electronics Laboratories

1958

by Columbia University

1926