1. Bickelhaupt, D. (n.d.). Soil pH: What it means.
http://www.esf.edu/pubprog/brochure/soilph/soilph.htm
2. Great Lakes Worm Watch. (n.d.). Sampling soils and soil characteristics.
http://www.nrri.umn.edu/worms/team/document.html
3. Hinkamp, D. (n.d.). Nutrients- vitamins for your soil.
https://extension.usu.edu/files/publications/factsheet/pub__3281455.htm
4. Hochmuth, G. (2011, August). Iron (Fe) nutrition in plants.
http://edis.ifas.ufl.edu/ss555
5. Kuhns, M., & Koenig, R. (2016). What is iron chlorosis and what causes it?
http://forestry.usu.edu/htm/city-and-town/tree-care/what-is-iron-chlorosis-and-what-causes-it
6. Whiting, D., Card, A., Wilson, C., & Reeder, J., Ph.D. (2015, October). Iron chlorosis.
http://www.ext.colostate.edu/mg/gardennotes/223.html#compaction
7. Zuzek, K., & Zlesak, D. (n.d.). Iron and manganese deficiencies in woody plants.
http://www.extension.umn.edu/garden/yard-garden/trees-shrubs/iron-chlorosis/
8. E.S.S.R.E. (2016) E.S.S.R.E. Microclimate Data Base.
http://essre.rpcs.org/ESSREMicroclimateSurvey.htm
