1. Directive 2001/80/EC of the European Parliament and of the Council of 23 October 2001 on the limitation of emissions of certain pollutants into the air from large combustion plants.
2. Ots, A. Oil Shale Fuel Combustion. – Tallinn: 2006. 833 p.
3. Arro, H., Prikk, A. Improving operation of wet gas cleaning equipment by dilution of circulating wash solution to avoid gypsum deposits // Oil Shale. l996. Vol. 13, No. 1. P. 73–78.
4. Aunela, L., Häsänen, E., Kinnunen, V., Larjava, K., Mehtonen, A., Salmikangas, T., Leskelä, J., Loosaar, J. Emissions from Estonian oil shale power plants // Oil Shale. l995. Vol. l2, No. 2. P. 165–177.
5. Öpik, I. Influence of Oil Shale Mineral Matter on the Boilers Operating Conditions. – Tallinn: Estonian State Publishing House, 1961 [in Russian, summary in English].
6. Ots, A. Processes in Steam Generators During the Burning of Oil Shale and Kansk-Achinsk Coals. – Moscow: Energy, 1977 [in Russian, summary in English].
7. Rundõgin, J. Low-Temperature Combustion of Oil Shale. – Leningrad: 1987 [in Russian, summary in English].
8. Kaljuvee, T., Trikkel, A., Kuusik, R. Reactivity of oil shale ashes towards sulphur dioxide. 1. Activation of high-temperature ashes // Oil Shale. l997. Vol. 14, No. 3. P. 393–407.
9. Kuusik, R., Kaljuvee, T., Trikkel, A., Arro, H. Reactivity of oil shale ashes towards sulphur dioxide. 2. Low-temperature ashes formed by using CFBC technology // Oil Shale. l999. Vol. 16, No. 1. P. 51–63.
10. Kuusik, R., Kaljuvee, T., Veskimäe, H., Roundygin, Yu., Keltman. A. Reactivity of oil shale ashes towards sulphur dioxide. 3. Recurrent use of ash for flue gas purification // Oil Shale. l999. Vol. 16, No. 4. P. 303–313.
11. Trikkel, A., Kuusik, R. Modeling of decomposition and sulphation of oil shale carbonates on the basis of natural limestone [Presented at Symposium on Oil Shale in Tallinn, Estonia, November 18–21, 2002] // Oil Shale. 2003. Vol. 20, No. 4. P. 491–500.
12. Greg, S. Adsorption, Surface Area and Porosity. – Moskva: Mir, 1984 [in Russian, summary in English].
13. Zeger, K. Additive dry method of flue gases cleaning from sulphur oxides // Energy Facilities Abroad. 1987. No. 5. P. 11–15 [in Russian, summary in English].
14. Brice, H. The first results regarding to reduction of SO2 emissions in 600 MW energy unit 5 in Provans power plant // Kraftwerkstechnik. 1987. Vol. 67, No. 7. P. 717–723 [in German].
15. Kotler, V. Nitrogen Oxides in Flue Gases from Boilers. – Moscow: Energoatomizdat, 1987 [in Russian, summary in English].
16. Leikert, K. The reduction of NOx emissions by the use of primary methods in a different burning chambers // VGB Kraftwerkstechnik. 1986. Vol. 66, No. 7. P. 631–637 [in German].
17. Jaborski, I. The technologically techniques of solid fuel combustion as methods for prevention of nitrogen emissions. // Thermal Engineering. 1995. No. 2. P. 17–23 [in Russian, summary in English].
18. Weber, E. Nitrogen oxide – Bremsen // Energy. 1986. Vol. 38, No. 4. P. 10–15 [in Germany, summary in English].
19. Macphail, J., King, L. New Laws prompt focus on low NOx options // Modern Power Systems. 1999. November. P. 29–33.
20. Sidorkin, V., Kniga, A., Rakitina, N. The opportunity of NOx emissions reduction for the pulverized oil shale fired boilers // Oil Shale. 1991. Vol. 8, No. 4. P. 355–359.
21. Hämäla, S. LIFAC cuts SOx in Finland // Modern Power Systems. 1986. Vol. 6. P. 87–91.
22. Ryyppö, M., Ekman. I. Improving the performance of LIFAC FGD in Chinese boilers // Modern Power Systems. 2000. Vol. 20, No. 11, P. 31–32.
23. Nolan, P. Desulfurization of flue gases at thermal power plants // Energetics. 1995. No. 6. P. 15–17; No. 7. P. 13–16 // Thermal Engineering. 1994. No. 6. P. 23–27 [in Russian, summary in English].
24. Overview of up-to-Date Methods of Flue Gases Cleanings from Sulfur Oxides and Utilization of By-Products. – SPO ORGRES, Moscow, 1993 [in Russian].
25. Beljaikin, V. Choice about desulphurization methods of flue gases at thermal power plants // Power Plants. 2000. No. 5. P. 14–18 [in Russian, summary in English].
26. Šmigol, I. Flue gas desulfurization technology for coal-fired thermal power plants of the Russian Federation // Electric Power Plants. 2006. No. 6. P. 27–35 [in Russian, summary in English].
27. Šmigol, I. Prospects for the use of sulfur removal facilities at thermal power plants in Russia // Energetic. 2007. No. 1. P. 12–15 [in Russian, summary in English].