http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
RETC code for quantifying the hydraulic functions of unsaturated soils
Robert S. Kerr Environmental Research Laboratory
by M.Th. van Genuchten, F.J. Leij, and S.R. Yates.
"U.S. Salinity Laboratory, U.S. Department of Agriculture."
Includes bibliographical references (pages 52-55).