1. Bioremediation of weathered-building stone surfaces
2. USEPA Primer for Municipal Wastewater Treatment Systems www.epa.gov/owm/primer.pdf 2009
3. USEPA An Analysis of Composting as an Environmental Remediation Technology http://www.epa.gov/waste/conserve/rrr/composting/pubs/index.htm 2009
4. Biofiltration of Air: A Review
5. BCC Market Research http://www.marketresearch.com/product/display.asp?productid=1300222&g=1 2009