Pervasive Arctic lead pollution suggests substantial growth in medieval silver production modulated by plague, climate, and conflict - McConnell, JR; Chellman, NJ; Wilson, AI; Stohl, A; Arienzo, MM; Eckhardt, S; Fritzsche, D; Kipfstuhl, S; Opel, T; Place, PF; Steffensen, JP (National Academy of Sciences, 2019)