Experience of Estonian oil shale combustion based on CFB technology at Narva Power PlantsHotta, A.; Parkkonen, R.; Hiltunen, Matti; Arro, Hendrik; Loosaar, Jüri; Parve, Teet; Pihu, Tõnu; Prikk, Arvi; Tiikma, ToomasOil shale2005 / 4S, p. 381-397 https://artiklid.elnet.ee/record=b2352607*est