1. J. A. Anderson, and V. G. Martin(1943 ). Probe for sampling deep grain bins.Winnipeg Gram Research Laboratory, Paper53 .
2. E. Bealing(1939 ). The handling and storing of grain in bulk. Pamphlet no. 16, Technical Education Series . National Joint Industrial Council for the Flour Milling Industry, London.
3. T. A. Oxley(1944 ). The properties of grain in bulk. IV. A simple gasometric apparatus for the estimation of carbon dioxide . Chem. & Ind.p. 24 .