"Watchmaker" Elis Sidenbladh, "History of impurity and watch technology" Hj. Tallqvist, "Horologium mirabile Lundense" Wåhlin."Rules for the accurate measurement of time by clocks" Urban Jürgensen, Copenhagen, 1839.
"Watchmaker" Elis Sidenbladh, "History of impurity and watch technology" Hj. Tallqvist, "Horologium mirabile Lundense" Wåhlin."Rules for the accurate measurement of time by clocks" Urban Jürgensen, Copenhagen, 1839.