1William Thornton to Thomas Jefferson, 20 January 1812 (Jefferson Papers)
Whitlow, Charles; and proposed Washington botanical garden [index entry]
2Thomas Jefferson to John Bradbury, 21 March 1812 (Jefferson Papers)
Whitlow, Charles; and proposed Washington botanical garden [index entry]
3William Thornton to Thomas Jefferson, 19 February 1817 (Jefferson Papers)
Whitlow, Charles; and proposed Washington botanical garden [index entry]