1. Institute for the Protection of Cultural Heritage of Slovenia; Research Institute, Conservation Centre; Poljanska 40 SI-1000 Ljubljana Slovenia
2. Museum Conservation Institute; Smithsonian Institution; 4210 Silver Hill Rd. Suitland MD 20746 USA
3. University of Ljubljana; Faculty of Chemistry and Chemical Technology; Aškerčeva 5 SI-1000 Ljubljana Slovenia
4. Slovenian National Building and Civil Engineering Institute; Dimičeva 12 SI-1000 Ljubljana Slovenia