Found in articles
2002, Pyroclastic Density Currents and the Sedimentation of Ignimbrites. Geological Society of London Memoir 27, 143pp. "MSH Pyroclastic flow [USGS]"
Machine Yamamoto, Takahiro; Takarada, Shinji; Suto, Shigeru (1993). "Pyroclastic flows from the 1991 eruption of Unzen volcano, Japan". Bulletin of Volcanology