Open-air deposition of Estonian oil shale ash : formation, state of art, problems and prospects for the abatement of environmental impactKuusik, Rein, keemik; Uibu, Mai; Kirsimäe, Kalle; Mõtlep, Riho; Meriste, TõnisOil shale2012 / p. 376-403 : illhttps://kirj.ee/public/oilshale_pdf/2012/issue_4/Oil-2012-4-376-403.pdf