format
a numeric vector of nickel concentrations (ppb)source
USEPA. (2009). Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities, Unified Guidance.
EPA 530/R-09-007, March 2009. Office of Resource Conservation and Recovery Program Implementation and Information Division.
U.S. Environmental Protection Agency, Washington, D.C. p.9-18.
USEPA. (2010). Errata Sheet - March 2009 Unified Guidance.
EPA 530/R-09-007a, August 9, 2010. Office of Resource Conservation and Recovery, Program Information and Implementation Division.
U.S. Environmental Protection Agency, Washington, D.C.