The Work of Water, Duff, A. Wilmer. No. 18 Leaflet, On Nature Study, Prepared by the Faculty of Purdue University. Especially adapted to the use of children in schools in rural districts, 1898

The Work of Water, Duff, A. Wilmer. No. 18 Leaflet, On Nature Study, Prepared by the Faculty of Purdue University. Especially adapted to the use of children in schools in rural districts, 1898, MSF 109, File 2, Item 4, Communal Collections Box: 20, Folder: 2, Item: 4. A. Wilmer Duff papers, MSF 109. Purdue University Archives and Special Collections. https://archives.lib.purdue.edu/repositories/2/archival_objects/48421 Accessed April 29, 2025.