Humboldt an <persName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0012873 http://d-nb.info/gnd/116442921">A.-P. de Candolle</persName>, <placeName xmlns="http://www.tei-c.org/ns/1.0" ref="https://edition-humboldt.de/H0008129 https://www.geonames.org/2988507">Paris</placeName>, 7. September 1820. Conservatoire et jardin botanique de la ville de Genève, Bibliothèque.