1. Institute of Mathematics P.J. Šafárik Univesity in Košice Trieda SNP 1 SK–040 11 Košice Slovakia
2. Department of Applied Statistics and Linz Institute of Technology Johannes Kepler University Altenbergerstraße 69 4040 Linz Austria
3. Institute of Statistics Universidad de Valparaíso Blanco 951 2360102 Valparaíso Chile