1. Associated General Contractors (AGC). (2002). Concrete recycling facts 〈http://www.agc.org/Environmental_Info/concrete_facts.asp〉 (May 30 2002).
2. BEES (Building for Environmental and Economic Sustainability) technical manual and user’s guide version 2.0 . (2000). National Institute of Standards and Technology Gaithersburg Md.
3. Bolen W. P. (2000). “Sand and gravel construction.” 2000 U.S. Geological Survey minerals handbook U.S. Geological Survey Reston Va.
4. Bonda P. (2000). “GSA wants you!” Green@Work July/August.
5. Bureau of Transportation Statistics (BTS). (2000). “National transportation statistics 2000.” Technical Rep. No. BTS01-01 Washington D.C.