1. University of Chemistry and Technology in Prague, Department of Physics and Measurements, Technická 5, Praha, Czech Republic
2. Comenius University in Bratislava, Faculty of Natural Sciences, Department of Landscape Ecology, Ilkovičova 6, Bratislava 842 48, Slovakia
3. University of South Bohemia, Faculty of Education, Department of Physics, Jeronýmova 10, České Budějovice, Czech Republic
4. Charles University and General University Hospital in Prague, First Faculty of Medicine, Institute of Immunology and Microbiology, Studničkova 7, Praha, Czech Republic