Koponen, Matti2021-11-112021-11-112001http://hdl.handle.net/2003/4055910.17877/DE290R-22428enhttps://creativecommons.org/licenses/by-nc/4.0796100m the first in the 20th centuryresearch datahttps://eldorado.tu-dortmund.de/handle/2003/25362https://eldorado.tu-dortmund.de/handle/2003/25404