Horwell, C., Braña, L., Sparks, R., Murphy, M., & Hards, V. (2001). A geochemical investigation of fragmentation and physical fractionation in pyroclastic flows from from the Soufriere Hills volcano, Montserrat. Journal of Volcanology and Geothermal Research, 109(4), 247-262. https://doi.org/10.1016/s0377-0273%2800%2900319-x