1. a 750 West Greenwich Place, Palo Alto, California, 94303
2. b All-Russian Geological Research Institute (VSEGEI) , Sredniy Prospect 74, St. Petersburg, 199026, Russia
3. c Central Research Institute of Geological Prospecting for Base and Precious Metals (TsNIGRI) , Varshavskoye Shosse 129b, Moscow, 113545, Russia
4. d Taymyrgeolkom , Post Box 1374, Noril'sk, 663300, Russia