Northern Lights Oliver Collectors - Hart-Parr #3 in a promotional photo with a new Oliver Hart-Parr 18-28 tractor. This was after Oliver Farm Equipment Company bought the tractor back for historical preservation.
The Hart-Parr Little Devil - Farm Collector
Hart Parr | Manitoba Agricultural Museum
Hart-Parr 20 Tractor | Print | Wisconsin Historical Society
Ruminations on a Hart-Parr 18-36H Tractor (1930) | Jack Elliott's Santa Barbara Adventure
Tractor Pioneers and the Hart-Parr 30-60 | Octane Press