1. Agri-land maps, 1970–1998. Agri-land property ownership maps, plat book & guide (all counties, all years). San Mateo, CA: Echoe-Map Pub., Scale [1:31680].
2. Characterization of soil quality: physical and chemical criteria;Arshad;American Journal of Alternative Agriculture,1992
3. A landscape-scale study of soil quality in three prairie farming systems;Boehn;Soil Science Society of America Journal,1997
4. Evaluation of selected soil physical, chemical and biological parameters as indicators of soil productivity;Bowman,1990
5. Quantitative indicators of soil quality: a minimum data set;Doran,1996