An interview with Alvar Soesoo, the director of the Geological Survey of EstoniaSoesoo, AlvarYearbook 2018 / Geological Survey of Estonia2019 / p. 6-7 : portr https://www.egt.ee/sites/default/files/content-editors/aastaraamat/egt_aastaraamat_eng_web.pdf https://www.ester.ee/record=b5231713*est