Niechajev, Igor http://orcid.org/0000-0003-2214-2774
Article History
Received: 6 October 2017
Accepted: 26 April 2018
First Online: 16 May 2018
Compliance with ethical standards
:
: 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. For this type of retrospective study, formal consent is not required.
: Informed consent was obtained from all individual participants included in this study.
: Igor Niechajev declares that he has no conflict of interest.