TY  - RPRT
TI  - Field determination of microgram quantities of niobium in rocks
AU  - F. N. Ward
AU  - A. P. Marranzino
PY  - 2002
DO  - 10.1021/ac60104a034
UR  - https://pubs.usgs.gov/publication/70011003
ID  - 70011003
ER  -