@article {637,
	title = {An Ascent of Popocatepetl},
	volume = {V},
	year = {1898},
	keywords = {ascent, Douglass, Popocatepetl},
	author = {Douglass, A.E.}
}
@booklet {636,
	title = {An Ascent of Popocatepetl},
	year = {1897},
	keywords = {ascent, Douglass, Popocatepetl},
	author = {Douglass, A.E.}
}
