1. Report on Critical Raw Materials for the EU—European Commission, May 2014
http://www.google.pt/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB4QFjAAahUKEwj0q5HDpdHIAhVCURoKHZwgCBQ&url=http%3A%2F%2Fec.europa.eu%2FDocsRoom%2Fdocuments%2F10010%2Fattachments%2F1%2Ftranslations%2Fen%2Frenditions%2Fnative&usg=AFQjCNEF6SkHHErPeB2gXS_dxBBFtlw_7A&sig2=qkh5AeKsO4cyRpuIZtVrWQ
2. Johnson Matthey, Precious Metals Management
http://www.platinum.matthey.com/about-pgm/applications
3. Recycling the Platinum Group Metals: A European Perspective
4. Extractive Metallurgy of Nickel, Cobalt and Platinum-Group Metals;Crundwell,2011
5. Oxidative leaching process with cupric ion in hydrochloric acid media for recovery of Pd and Rh from spent catalytic converters