Federal Reserve Bank of San Francisco. "Learning and Shifts in Long-Run Productivity Growth : Working Paper 2004-04, Working Paper 2004-04" in Working Papers (Federal Reserve Bank of San Francisco) (March 25, 2004). https://fraser.stlouisfed.org/title/7038/item/639170/content/pdf/frbsf_wp2004-04, accessed on March 27, 2025.