Donehoo, George P. Pennsylvania: A History. New York: Lewis Historical Publishing Company, 1926.

Includes excellent, if somewhat dated, histories of the political administrations of each Pennsylvania governor between Andrew Curtin (1861-1867) and Gifford Pinchot (1923-1927).

Referenced in:
Pennsylvania Politics 1865-1930.
William A. Stone
James A. Beaver
John K. Tener [Politics]
William C. Sproul