User talk:2800:A4:1335:7000:492D:A767:F512:B9A6

Reference to "Walker, Alexander (1822). «Part 1». Colombia, relación geográfica, topográfica, agrícola" was added as example. Palacios book is the source of Humboldt, as Humboldt noted in a footnote to his book, that is already cited here. Not mentioning Palacios here as the primary source would be misleading.