Federal Reserve Bank of San Francisco. "A State Level Database for the Manufacturing Sector : Working Paper 2009-21 : Construction and Sources, Working Paper 2009-21" in Working Papers (Federal Reserve Bank of San Francisco) (October 2, 2009). https://fraser.stlouisfed.org/title/7038/item/639307/content/pdf/frbsf_csip_wp2009-21, accessed on March 24, 2025.