The effect of oil shale ash and mixtures of wood ash and oil shale ash on the biomass formation of Silver birch and Scots pine seedlings on a cutaway peatlandSepp, Leno; Aguraijuja, Karin; Tilka, Mari; Ots, Katri; Orru, MallInternational IX Oil Shale Conference 2017 "Oil Shale Industry in Circular Economy" : 15th-16th November 2017, [Jõhvi], Ida-Viru County, Estonia : summary2017 / p. 34 http://www.ester.ee/record=b4751282*est