Funding for this research was provided by:
Swedish Institute (205/2015)
Estonian Ministry of Education and Research (IUT34-17)
Estonian Research Council (3.2.1002.11-0002)
Received: 8 March 2017
Accepted: 25 March 2018
First Online: 31 March 2018
Compliance with ethical standards
: The authors declare that they have no financial or non-financial conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the University of Tartu research committee and with the 1964 Helsinki declaration and its later amendments.
: After informing about the survey objectives and how the data would be used for the research, the individuals who voluntarily confirmed their willingness, were involved in the survey.