1. Raask, E. Mineral Impurities in Coal Combustion. Behaviour, Problems and Remedial Measures. – Hemisphere Publishing Corporation, 1985, 467 pp.
2. Öpik, I. Influence of Oil Shale Mineral Matter on Boiler Operating Conditions. – ERK, Tallinn, 1961, 249 pp. [in Russian].
3. Ots, A. Processes in Steam Generators during the Burning of Oil Shale and Kansk-Achinsk Basin Coals. – Energy, Moscow, 1977, 312 pp. [in Russian].
4. Mägi, R. Workout of Methods for Determination of Abrasion Characteristics of Industrial Dusts Wearing Rotors of Centrifugal Compressors. – Candidate's dissertation, TUT, Tallinn, 1982, 154 pp. [in Russian].
5. Stoerikovich, M., Katkovskaja, K., Serov, E. Steam Generators of Power Stations. – Energy, Moscow, 384 pp. [in Russian].
6. Drozdov, V. F. Heating and Ventilation. Part II. Ventilation. – High School, Moscow, 1984, 263 pp. [in Russian].