http://www.mcall.com/news/local/mc-carbon-county-beth-doe-20141129-story.html An interesting artikel, some peaces from it about the isotopes.
The findings suggest the woman found at the bottom of a bridge wasn't a local girl. Rather, she probably came from western or central Europe. She likely moved to the United States as a child or teen and lived somewhere in the Southeast.
If the findings are correct, Beth Doe was born and spent her early childhood in western or central Europe. She moved to the United States as a child or a teenager. She spent at least five to 10 years in the United States before her murder.
She also most likely became pregnant in this country. And she probably lived in the Southeast, possibly somewhere in eastern Tennessee.
The science is inexact, McAndrew said, although there is no telling what breakthrough will lead them down the proper path toward identifying Beth Doe. Already, McAndrew and his fellow officers are using the evidence to look into missing persons cases in the Southeast.
So she came to the USA between 1966 and 1971, born between 1954 and 1960.