1David Bailie Warden to Thomas Jefferson, 17 April 1809 (Jefferson Papers)
Humboldt, Friedrich Wilhelm Heinrich Alexander, Baron von; sends greetings to TJ [index entry]
2David Bailie Warden to Thomas Jefferson, 27 October 1809 (Jefferson Papers)
Humboldt, Friedrich Wilhelm Heinrich Alexander, Baron von; sends greetings to TJ [index entry]
3Lafayette to Thomas Jefferson, 20 September 1810 (Jefferson Papers)
Humboldt, Friedrich Wilhelm Heinrich Alexander, Baron von; sends greetings to TJ [index entry]
4David Bailie Warden to Thomas Jefferson, 14 July 1816 (Jefferson Papers)
Humboldt, Friedrich Wilhelm Heinrich Alexander, Baron von; sends greetings to TJ [index entry]