Received: 7 November 2018
Accepted: 20 March 2019
First Online: 11 April 2019
: Not applicable (Review Article without involving animals, human participants, human data or human tissue).
: Not applicable.
: The authors, Michael-Alex, er Malahias, Lazaros Kostretzis, Efstathios Chronopoulos, Emmanouil Brilakis, Gregorios Avramidis, and Emmanouil Antonogiannakis, declare that they have no competing interests.
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