Funding for this research was provided by:
Text and Data Mining valid from 2019-04-15
First Online: 15 April 2019
Conflict of interest
: M.E. ten Haaf, M. Bax, J.M. ten Berg, J. Brouwer, A.W. van’t Hof, R.J. van der Schaaf, P.R. Stella, R.M. Tjon Joe Gin, P.A. Tonino, A.G. de Vries, F. Zijlstra, E. Boersma and Y. Appelman declare that they have no competing interests.