http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
comparison of dynamic pile driving formulas with the wave equation
by Lee L. Lowery, Jr., James R. Finley, Jr., and T. J. Hirsch.
"Piling behavior, Research study number 2-5-62-33, sponsored by the Texas Highway Department in cooperation with the U.S. Department of Transportation, Federal Highway Administration, Bureau of Public Roads."