Lambova, Sevdalina Nikolova
Müller-Ladner, Ulf
Article History
Received: 7 September 2017
Accepted: 8 January 2018
First Online: 1 February 2018
Compliance with ethical guidelines
:
: S.N. Lambova and U. Müller-Ladner declare that they have no competing interests.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.