Bennett, J. Michael; Rhetoric, Emeritus; Hicks, Dale R.; Naeve, Seth L.; Bennett, Nancy Bush (2014). The Minnesota Soybean Field Book(PDF). St Paul, MN: University of Minnesota Extension. p. 84. Archived from the original(PDF) on 2013-09-30. Retrieved 21 February 2016.
web.archive.org
Bennett, J. Michael; Rhetoric, Emeritus; Hicks, Dale R.; Naeve, Seth L.; Bennett, Nancy Bush (2014). The Minnesota Soybean Field Book(PDF). St Paul, MN: University of Minnesota Extension. p. 84. Archived from the original(PDF) on 2013-09-30. Retrieved 21 February 2016.
