- Woodward propeller governor with a beta valve.
- WOODWARD SERIES 1307 AIRCRAFT MAIN ENGINE CONTROL THEORY OF OPERATION.
- A non-Woodward aircraft propeller governor(Curtis-Wright Co.).
- From the archives.
- From the archives.
- 1880 catalog
- 1878 Rockford
- Rockford factory history.
- Vintage Rockford map.
- Rockford history.
- Rockford history.
- Rockford history.
- 1896-County-Fair-Collection
- 1896
- Rockford history 1895.