T. D. McLennan

Field trial of a pair production gauge for the on-line determination of ash in coal on a conveyor belt

E. Howells, B. Sowerby, W. Ellis, 1984 .

On-line determination of the ash content of coal using a “Siroash” gauge based on the transmission of low and high energy γ-rays

E. Howells, J. Watt, C. E. Campbell, 1983 .