Bureau of Mines / Minerals yearbook metals, minerals, and fuels 1972
Year 1972, Volume 1 (1972)
Ampian, Sarkis G.
Clays, pp. 301-327 ff. PDF (2.9 MB)
http://rightsstatements.org/vocab/NoC-US/1.0/| As a work of the United States government, this material is in the public domain.| For information on re-use see: http://digital.library.wisc.edu/1711.dl/Copyright