IEA International Conference on Clean and Efficient Use of Coal Budapest & International Energy Agency. (1993). Clean and efficient use of coal: The new era for low-rank coal : Budapest, Hungary, February 1992 : conference proceedings. International Energy Agency; Organisation for Economic Co-operation and Development.
Παραπομπή σε μορφή Chicago (17η εκδ.)IEA International Conference on Clean and Efficient Use of Coal Budapest και International Energy Agency. Clean and Efficient Use of Coal: The New Era for Low-rank Coal : Budapest, Hungary, February 1992 : Conference Proceedings. Paris, France: International Energy Agency; Organisation for Economic Co-operation and Development, 1993.
Παραπομπή σε μορφή MLA (9th εκδ.)IEA International Conference on Clean and Efficient Use of Coal Budapest και International Energy Agency. Clean and Efficient Use of Coal: The New Era for Low-rank Coal : Budapest, Hungary, February 1992 : Conference Proceedings. International Energy Agency; Organisation for Economic Co-operation and Development, 1993.