Creating a crop maze with GPS

Chicago citation style
Roberson, Gary T., University of North Carolina (System). Creating a crop maze with GPS. 2004-06. Retrieved from the Digital Public Library of America, http://digital.ncdcr.gov/cdm/ref/collection/p249901coll22/id/3682. (Accessed October 18, 2018.)
APA citation style
Roberson, Gary T., University of North Carolina (System), (2004-06) Creating a crop maze with GPS. Retrieved from the Digital Public Library of America, http://digital.ncdcr.gov/cdm/ref/collection/p249901coll22/id/3682
MLA citation style
Roberson, Gary T., University of North Carolina (System). Retrieved from the Digital Public Library of America <http://digital.ncdcr.gov/cdm/ref/collection/p249901coll22/id/3682>.
Note: These citations are programmatically generated and may be incomplete.