Klug, Günter http://orcid.org/0000-0001-7146-2630
Gallunder, Manuela
Hermann, Gerhard
Singer, Monika
Schulter, Günter
Article History
Received: 28 June 2019
Accepted: 20 November 2019
First Online: 3 December 2019
Ethics approval and consent to participate
: No ethical approval required.
: Not applicable.
: The authors declare that they have no competing interests.