http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Sand and gravel mining, and quarrying and blasting for crushed stone and other construction minerals
a working paper prepared for the Committee on Surface Mining and Reclamation, Board on Mineral and Energy Resources, Commission on Natural Resources, National Research Council
Committee on Surface Mining and Reclamation.
Appendix 1 to the Committee's Surface mining of non-coal minerals.