Published on in Vol 20, No 10 (2018): October
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/9253, first published
.
1 Faculty of Economics and Business, Universitat Oberta de Catalunya, Barcelona, Spain
2 Applied Economics Department, King Juan Carlos University, Madrid, Spain
3 Faculty of Health Sciences, Universitat Oberta de Catalunya, Barcelona, Spain
*all authors contributed equally