TY  - RPRT
TI  - ISOPLOT; a plotting and regression program for radiogenic-isotope data; version 2.53
AU  - K.R. Ludwig
PY  - 1991
DO  - 10.3133/ofr91445
UR  - https://pubs.usgs.gov/publication/ofr91445
ID  - ofr91445
ER  -