1Robert Patterson to Thomas Jefferson, 2 December 1815 (Jefferson Papers)
Hassler, Ferdinand Rudolph; and U.S. Coast Survey [index entry]
2Thomas Jefferson to Wilson Cary Nicholas, 19 April 1816 (Jefferson Papers)
Hassler, Ferdinand Rudolph; and U.S. Coast Survey [index entry]
3Enclosure: Ferdinand R. Hassler to Robert Patterson, 2 December 1816 (Jefferson Papers)
Hassler, Ferdinand Rudolph; and U.S. Coast Survey [index entry]
4Alden Partridge to Thomas Jefferson, 20 February 1818 (Jefferson Papers)
Hassler, Ferdinand Rudolph; and U.S. Coast Survey [index entry]
5Ferdinand R. Hassler to Thomas Jefferson, 10 December 1819 (Jefferson Papers)
Hassler, Ferdinand Rudolph; and U.S. Coast Survey [index entry]