Tomczak, TorstenTorstenTomczakKarg, MichaelMichaelKargAlbers, SönkeHassman, VolkerSomm, FelixTomczak, Torsten2023-04-132023-04-131999https://www.alexandria.unisg.ch/handle/20.500.14171/60545deKundenaquisitionbook section