Vossen, T. E. http://orcid.org/0000-0002-5276-1114
Henze, I.
Rippe, R. C. A.
Van Driel, J. H.
De Vries, M. J.
Funding for this research was provided by:
Leiden University
Article History
First Online: 30 April 2019
Compliance with Ethical Standards
:
: The authors declare that they have no conflict of interest.
: Ethical approval was obtained from the ethics committee of Leiden University Graduate School of Teaching. We obtained passive informed consent from the teachers via an instruction letter. All participating teachers did so voluntarily.