Text and Data Mining valid from 2018-06-01
Received: 29 March 2018
Accepted: 18 May 2018
First Online: 1 June 2018
Compliance with ethical standards
: Ethical approval: All procedures performed in studies involving human participants were in accordance with the ethical standards of the Ethics Committee of the University of Crete & Harokopio University and with 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants (their parents) included in the study.
: The authors declare that they have no conflict of interest.