Biblio
“A Trip To The Summit Of Orizaba, The Altitudes Of Orizaba And Popocatepetl Effects Of High-Mountain Climbing”. Appalachia Vol. VIII (No. 4). Appalachia.
. 1898. 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)“An Ascent Of Popocatepetl”. Popular Astronomy. Popular Astronomy.
. 1898. Douglass, AE_An Ascent of Popocatepetl_1898.pdf (6.69 MB) . 1897. Douglass, AE_An Ascent of Popocatepetl_1897.pdf (1.92 MB)