TY - RPRT TI - Standard Reference Materials : Summary of the coal, ore, mineral, rock, and refractory standards issued by the National Bureau of Standards/ AU - Gills, T E AU - Mavrodineanu, R PY - 1985 PB - National Institute of Standards and Technology CY - Gaithersburg, MD SN - NBS SP 260-97 DO - 10.6028/NBS.SP.260-97 ER -