https://www.nps.gov/lecl/learn/historyculture/york.htm
https://www.smithsonianmag.com/history/york-explored-west-lewis-and-clark-his-freedom-wouldnt-come-until-decades-later-180968427/
https://www.pbs.org/lewisandclark/inside/york.html
http://montanakids.com/history_and_prehistory/lewis_and_clark/york.htm