Author
Geological Survey (U.S.),
5
Ruppel, Edward Thompson, 1925-
4
Cressman, Earle Rupert, 1923-
2
Harrison, Jack Edward, 1924-
2
Earhart, Robert L.
1
Earhart, Robert L.,
1
Geological Survey (U.S.)
1
Kleinkopf, M. Dean 1926-2015
1
Kleinkopf, M. Dean 1926-2015,
1
Lopez, David A.
1
Lopez, David A.,
1
Montana Bureau of Mines and Geology
1
Mudge, Melville R., 1921-2009
1
Mudge, Melville R., 1921-2009,
1
Smith, Donald L., 1940-
1