Tractor principles the action, mechanism, handling, care, maintenance and repair of the gas engine tractor This book, "Tractor principles the action, mechanism, handling, care, maintenance and repair of the gas engine tractor", by Roger B. Whitman, is a replication of a book originally published before 1920. It has been restored by human beings, page by page, so that you may enjoy it in a form as close to the original as possible. This book was created using print-on-demand technology. Thank you for supporting classic literature.