Graebner, William (1977). "Federalism in the Progressive Era: A Structural Interpretation of Reform". The Journal of American History. 64 (2): 331–357. doi:10.2307/1901828. JSTOR1901828.
Graebner, William (1977). "Federalism in the Progressive Era: A Structural Interpretation of Reform". The Journal of American History. 64 (2): 331–357. doi:10.2307/1901828. JSTOR1901828.