- Vintage Woodward document history is fun!
- From the Oldwoodward.com archives.
- Limelight on the Lucas Aerospace Company history.
- Allis-Chalmers Manufacturing Company history.
- Allis-Chalmers Company history on governor theory.
- Allis-Chalmers Company history on governor theory.
- Allis-Chalmers Company history on governor theory.
- JAMES LEFFEL & COMPANY
- ILLUSTRATED HAND BOOK, CIRCA 1886.
- The James Leffel & Company's factory
- INTRODUCTION
- Page 4.
- Page 5.
- Page 6.
- Page 7.