Climate Change Position Statement Working Group (May 11, 2011). "Position Statement on Climate Change"(PDF). Working Group Rep. ASA, CSSA, and SSSA. Madison, WI. Retrieved January 21, 2019. {{cite web}}: |author= has generic name (help)
"Soils". Food and Agriculture Organization. Retrieved 19 February 2019.
harvard.edu
ui.adsabs.harvard.edu
Erik C Brevik (2013). "A Brief History of the Soil Science Society of America". Geophysical Research Abstracts. 14. Harvard University: EGU2013-67. Bibcode:2013EGUGA..15...67B.