1. Backman, R., Hupa, M., Uppstu, E: Tappi J. 70(6), (1987).
2. Backman, R., Skrifvars, B-J., Hupa, M., Siiskonen, P., Mäntyniemi, J: Journal of Pulp and Paper Science (JPPS) 22 (1996) 4: J119–J126.
3. Bryers, R. W.: Fireside behaviour of mineral impurities in fuels, from Marchwood 1963 to Palm Coast 1992, in Inorganic transformations and ash deposition during combustion (Ed: S. Benson), United Engineering Trustees Inc. 1992.
4. Hansen, P. F. B: Deposit formation in the convective path of a Danish 80MWth CFB-boiler co-firing straw and coal for power generation, presented at the Engineering Foundation Conference on the Impact of Mineral Impurities in Solid Fuel Combustion, Kona, Hawaii, USA, November 1997.
5. Harb, J. N., Smith, E. E: Prog. Energy Combust. Sci 16(3), 169 (1990).