Physicochemical or geochemical

• Cronin, S. J., Neall, V. E., Lecointre, J. A., Hedley, M. J., Loganathan, P., (2003), Environmental hazards of fluoride in volcanic ash: a case study from Ruapehu volcano, New Zealand, Journal of Volcanology and Geothermal Research, 121, 271-291, 10.1016/S0377-0273(02)00465-1