Text and Data Mining valid from 2019-05-22
Received: 20 March 2019
Accepted: 18 May 2019
First Online: 22 May 2019
Ethics approval and consent to participate
: The Ethics Committee of the Hellenic Open University granted permission for conducting the research. All the participants were initially informed about the aim of the study and reassured about their anonymity. They participated voluntarily and their written consent was required for further involvement in the research.
: Not applicable.
: The authors declare that they have no competing interests.