Though a linear relation is widely assumed to hold, experimental data suggest that almost 80% of tested materials do not satisfy this widely accepted linear behavior. See Kerley, G. I, 2006, "The Linear US-uP Relation in Shock-Wave Physics", arXiv:1306.6916; for details.
Hoyt, M (1 July 1979). User's manual for LASL shock Hugoniot data file (Report). Office of Scientific and Technical Information (OSTI). doi:10.2172/6177198. OSTI6177198.
Hoyt, M (1 July 1979). User's manual for LASL shock Hugoniot data file (Report). Office of Scientific and Technical Information (OSTI). doi:10.2172/6177198. OSTI6177198.