Al-Kaisi, M. (2000). Soil erosion: An agricultural production challenge. Iowa State University Extension and Outreach. (Accessed 27 August 2017).
Brady, N. C. & Weil, R. R. (2008). The nature and properties of soils. (14th ed.). United States: Pearson.
Crop Data Management Systems (CDMS). (2017). Label database. (Accessed 27 August 2017). Read more about Chapter 7: References