Newhall, Christopher G.; Self, Stephen (20 February 1982). "The Volcanic Explosivity Index (VEI): An Estimate of Explosive Magnitude for Historical Volcanism". Journal of Geophysical Research. 87 (C2): 1232. Bibcode:1982JGR....87.1231N. doi:10.1029/JC087iC02p01231.
Newhall, Christopher G.; Self, Stephen (20 February 1982). "The Volcanic Explosivity Index (VEI): An Estimate of Explosive Magnitude for Historical Volcanism". Journal of Geophysical Research. 87 (C2): 1232. Bibcode:1982JGR....87.1231N. doi:10.1029/JC087iC02p01231.