RESOURCES
Ferguson, B. K. 2005. Porous pavements. Boca Raton, FL: Taylor and Francis.
Urban, J. 2008. Up by roots: Healthy_structural soils and trees in the built environment.
Champaign, IL: International Society of Arboriculture.
Urban Horticulture Institute, Cornell University: CU Structural Soil.
http://www.hort.comell.edufuhif
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