Text and Data Mining valid from 2018-11-01
Received: 4 August 2018
Accepted: 6 November 2018
First Online: 12 January 2019
Compliance with ethical standards
: The study protocol was approved by the Institutional Ethics Committee.
: SS and ZVS declare that they have no conflict of interest.
: The authors declare that the study was performed in a manner conforming to the Helsinki declaration of 1975, as revised in 2000 and 2008 concerning human and animal rights, and the authors followed the policy concerning informed consent as shown on ExternalRef removed.
: The authors are solely responsible for the data and the content of the paper. In no way, the Honorary Editor-in-Chief, Editorial Board Members, or the printer/publishers are responsible for the results/ findings and content of this article.