Funding for this research was provided by:
Volkswagen Foundation (91474, 91474, 91474)
Deutscher Akademischer Austauschdienst (91562643)
Received: 15 March 2018
Accepted: 25 July 2018
First Online: 13 September 2018
Ethics approval and consent to participate
: The research and its procedures were approved by the ethical review committees of Bielefeld University in Germany and Koya University in the Kurdistan Region of Iraq.
: Not applicable.
: The authors declare that they have no competing interests.
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