Peer reviewed is your favorite flavor? There is plenty... http://rodaleinstitute.org/our-work/farming-systems-trial/farming-systems-trial-30-year-report/
Printed copy · Anthology Volume 4, page 321Printed copy from The Tender For Law Anthology, Volume 4, page 321 (printed 13 June 2014). Added by this site; not part of the Facebook export.