Schaefer, J.R., Larsen, J.F., and Unema, J.A., 2011, Digital elevation model (DEM) and shaded relief image of Okmok Caldera, 2010: Alaska Division of Geological & Geophysical Surveys Raw Data File 2011-6, 1 DVD, available online at http://www.dggs.dnr.state.ak.us/pubs/id/23223 .
link to ADGGS website with GIS files for download