- The Woodward Governor Company's Hydro Governor Market Share in 1991.
- Niagara Falls hydro history.
- An advertisement from the Cliff Papper Company from 1913.
- The Woodward Governor Company's Hydro Governor Market Share in 1991.
- The Woodward Governor Company's Hydro Governor Market Share in 1991.
- Circa 1913 advertisement.
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- HYDRO POWER MARKET HISTORY.
- History of the Cliff Papper Company in Niagara Falls, New York.
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- WISCONSIN HISTORY MAP.
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