1. APAS Clean Coal Technology Programme 1992–1994, “Combined Combustion of Biomass/Sewage Sludge and Coals”. Volume II: Final reports. Edited by the Institute for Process Engineering and Power Plant Technology, University of Stuttgart, for the European Commission, DG XII: Science, Research and Development, Stuttgart 1995 (ISBN 3–928123–16–5).
2. Baldacci, Bianchi, De Robertis, Paolicchi, Rognini. Tani: “Fireside Fouling During Caol/Biomass Co-Firing in a Circulating Fluidized Bed Combustor and a Pulverized Coal Power Plant”. In: APAS Clean Coal Technology Programme 1992–1994, “Combined Combustion of Biomass/Sewage Sludge and Coals”. Volume II: Final reports [1].
3. DIN 51370: “Bestimmung des Ascheschmelzverhaltens”, 5/1984
4. Heinzel, T.: “Ermittlung der Verschlackungs-und Verschmutzungsneigung von Kohle-/Biomasse-Mischungen bei der Verbrennung in Staubfeuerungen”. Diplomarbeit Nr. 2530. Institute for Process Engineering and Power Plant Technology ( IVD ), University of Stuttgart, 1994.
5. Juniper, Lindsay: “Applicability of Ash Slagging Indices” Australian Combustion Technology Center ACTC: Combustion News, Feb. 1995