- WOODWARD HYDRO CONTROL SYSTEMS SINCE 1870.
- Picture credit and Information courtesy of Diesel Progress North American KHL Group Americas LLC.
- Page 3. Information courtesy of the Diesel Progress North American KHL Group Americas LLC.
- Page 2. Information courtesy of Diesel Progress North American KHL Group Americas LLC.
- The Arrow A54 Gaseous Fuel Engine history.
- Brad's Diesel Engine History Project.
- The Arrow A54 Gaseous Fuel Engine data.
- The Arrow A54 Gaseous Fuel Engine data.
- The Black Point Legacy History Book.
- The Conrad Seipp Brewing Company.
- Brad's Brewery Industry History Project.
- The Black Point Legacy History Book.
- The Black Point Legacy History Book.
- Conrad Seipp's summer lakeside estate history.
- In memory of Conrad Seipp (1825-1890).