Martin, N. P.Fenster, W. E.Chambers, G. R.Radford, J. D.2019-09-182019-09-181983https://hdl.handle.net/11299/2072691 online resource (PDF, 6 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