by University of Kentucky

1923

by Northwestern University (Evanston, Ill.)

1920

by Northwestern University (Evanston, Ill.)

1920

by University of Minnesota. Northwest Experiment Station (Crookston, Minn.)

1917

by Ohio State University. Center for Vocational and Technical Education, United States. Office of Education

1972

by Yale University. Library

1901

by Yale University. Library

1901

by Northwestern University (Evanston, Ill.)

1919

by University of Oklahoma. Science and Public Policy Program

1979

by University of Minnesota

1928

by University of Minnesota

1927

by Colorado State University. Natural Resource Ecology Laboratory

1978