@book{Kleeis2020,
author = {Kleeis, Friedrich},
year = {2020},
language = {ger},
copyright = {https://creativecommons.org/public-domain/cc0/},
title = {Ratgeber für die Knappschaftsversicherung},
url = "http://dx.doi.org/10.17169/refubium-26758",
}