Sub-permafrost methane seepage from open-system pingos in Svalbard. - Hodson, Andrew J.; Nowak, Aga; Hornum, Mikkel T.; Senger, Kim; Redeker, Kelly; Christiansen, Hanne H.; Jessen, Søren; Betlem, Peter; Thornton, Steve F.; Turchyn, Alexandra V.; Olaussen, Snorre; Marca, Alina (Cryosphere, 2020)