Skrzypkowska, M
Myśliwska, J
Słomiński, B
Siebert, J
Gutknecht, P
Ryba-Stanisławowska, M
Article History
Received: 7 April 2014
Revised: 19 August 2014
Accepted: 22 August 2014
First Online: 9 October 2014
Competing interests
: The authors declare no conflict of interest.