Biblio
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Cogshall, WA, Douglass, AE_A Trip to the Summit of Orizaba, THe Altitudes of Orizaba and Popocatepetl Effects of High Mountain Climbing_1897.pdf (16.55 MB). “Report On The Chronology Phase Of The Bristlecone Pine Study”. Tucson: Laboratory of Tree-Ring Research.
Ferguson_Report on the Chronology Phase of the Bristlecone Pine Study.pdf (1.56 MB)