8[2]U.S.Bureau of the Budget.1967.Standard Metropolitan Statistical Areas.Washington,D.C.,p.vii.
9[3]U.S.Office of Management and Budget.Standards for Defining Metropolitan and Micropolitan Statistical Areas;Notice.http://www.whitehouse.gov/omb/fedreg/metroareas122700.pdf.
10[4]U.S.Office of Management and Budget.OMB Bullentin No.06-01 Corrected:Update of Statistical Area Definitions and Guidance on Their Uses.http://www.whitehouse.gov/omb/bulletins/fy2006/b06-01_rev_2.pdf.
