DOCUMENTS INCORPORATED BY REFERENCE (4VAC50-85).
Virginia Commercial Vegetable Production Recommendations for 2005, Virginia Cooperative Extension Service, Publication No. 456‑420
Electronic Field Office Technical Guide, Natural Resources Conservation Service, United States Department of Agriculture
Methods of Soil Analysis, Part 3, Chemical Methods, 1996, Soil Science Society of America/American Society of Agronomy
Recommended Methods of Manure Analysis, publication A3769, University of Wisconsin, 2003
Tucker, M.R. 1992. Determination of phosphorus by Mehlich 3 extraction. pg. 6-8. In S.J. Donohue (Ed.) Reference Soil and Media Diagnostic Procedures for the Southern Region of the United States. Southern Cooperative Series Bulletin No. 374
Virginia Phosphorus Index Version 2.0 Technical Guide, Revised October 2005, Virginia Tech