TY  - RPRT
TI  - Carbonatites of the world, explored deposits of Nb and REE— Database and grade and tonnage models
AU  - Vladimir I. Berger
AU  - Donald A. Singer
AU  - Greta J. Orris
PY  - 2009
DO  - 10.3133/ofr20091139
UR  - https://pubs.usgs.gov/publication/ofr20091139
ID  - ofr20091139
ER  -