Pb-210 and fly ash particles in ombrotrophic peat bogs as indicators of industrial emissionsVaasma, Taavi; Karu, Helen; Kiisk, Madis; Alliksaar, TiiuJournal of environmental radioactivity2017 / p. 78-86 : ill https://doi.org/10.1016/j.jenvrad.2016.07.027