Ren, W., D. Qiao, J. J. Ba, and G. Li. “Relationship Between the Height of the Compression Region and the Underflow Concentration of a Vertical Silo With Consecutive Discharge”. Journal of Mines, Metals and Fuels, vol. 65, no. 3, Mar. 2017, pp. 144-8, doi:10.18311/jmmf/2017/27033.