Owyang, Michael T. , Piger, Jeremy M. , Wheeler, Christopher H. and Wall, Howard J. "The Economic Performance of Cities: A Markov-Switching Approach, Working Paper 2006-056C," Working Papers (Federal Reserve Bank of St. Louis) (Revised December 2007). https://fraser.stlouisfed.org/title/9029/item/716382, accessed on September 9, 2026.