Rehm, G. W.Fenster, W. E.Grava, J.Malzer, G. L.2019-09-182019-09-181984https://hdl.handle.net/11299/2074071 online resource (PDF, 4 pages)This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu.enReport