by Purdue University. Agricultural Experiment Station

1906

by Purdue University, Lafayette, Ind. Engineering Extension Department

1930

by Purdue University. Dept. of Engineering Extension

1930

by Purdue University

1912

by Purdue University

1920

by Purdue University

1926

by Purdue University. Agricultural Experiment Station

1919

by Purdue University

1918

by Purdue University

1929

by Purdue University. Agricultural Extension Service

1914

by Purdue University

1925

by Purdue University. Agricultural Experiment Station

1901