Text and Data Mining valid from 2017-03-13
Received: 4 October 2016
Accepted: 10 February 2017
First Online: 13 March 2017
Compliance with ethical standards
: On behalf of all the authors, the corresponding author states that there is no conflict of interest.
: In conducting the present research, ethical guidelines were followed. All procedures performed were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Participation in the study was voluntary and the information provided was anonymous and confidential.
: Written informed consent was obtained from all participants prior to participation in the study.