- WOODWARD VR gateshaft Governor OFFSET CONTROL STANDARD BEFORE 1920
- A Woodward gateshaft governor by Celesta
- Vintage Hydroelectric Power Plant history.
- Vintage Hydroelectric Power Plant history.
- L & S ELECTRIC.
- HYDRO-QUEBEC
- VOITH HYDRO
- ANGELL WATER WHEEL COMPANY
- General Electric Company ad from 1919.
- THE LOMBARD GOVERNOR COMPANY, CIRCA 1919.
- A run of the river small hydro-electric power plant from 1915.
- The Pelton Water Wheel Company history, circa 1919.
- THE ELECTRIC LIGHT SYSTEM AT APPLETON, WISCONSIN.
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