babel.hathitrust.org/cgi/pt?id=wu.89097421655;view=1up;seq=1

Thought this was VERY interesting. There was a LOT of GOOD info in there as to which companies were serving which towns in Minnesota and there were some surprises in there such as finding out East Grand Forks was evidently served by NSP at one time (they must have torn up the franchise and went muni in the '30s).