Text and Data Mining valid from 2020-01-09
Received: 7 June 2019
Accepted: 31 December 2019
First Online: 9 January 2020
Compliance with ethical standards
: All authors (Jakob C.F. Gunneweg, Georgios F. Giannakopoulos, Wietse P. Zuidema, Niels A.A. Matheijssen, Ferco H. Berger) declare that they have no conflict of interest.