International intercomparison exercise of airborne gamma-spectrometric systems of the Czech Republic, France, Germany and Switzerland in the Framework of the Swiss Exercise ARM17 - Butterweck, Gernot; Bucher, Benno; Gryc, Lubomir; Debayle, Christophe; Strobl, Christopher; Maillard, Stéphane; Thomas, Michael; Helbig, Alexandra; Krol, Inge; Chuzel, Sonia; Couvez, Céline; Ohera, Marcel; et al. (PSI-Bericht, 2018)