Hallman, Christine Lee. 2001. ?Spatial Relationships In Frost-Damaged High-Elevation Pines And Links To Major Volcanic Eruptions?. Geoscience. Geoscience. Tucson: University of Arizona.

Dewitt, E, and Martha Hyde  Ames. 1978. Tree-Ring Chronologies Of Eastern North America. Chronology Series Iv. Vol. 1. Chronology Series Iv. Tucson: Laboratory of Tree-Ring Research.