More than obvious: better methods for interpreting nondetect data.
Helsel
Dennis R
DR
U.S. Geological Survey, Lakewood, CO, USA.
D004463:Ecology / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods*; D007287:Inorganic Chemicals / Q000032:analysis*; D009930:Organic Chemicals / Q000032:analysis*; D013223:Statistics as Topic / Q000379:methods*
D007287:Inorganic Chemicals; D009930:Organic Chemicals