Suggested citation for smwrQW:

  Lorenz, D.L., in preparation smwrQW--An R Package for Managing and
  Analyzing Water-Quality Data, Version 0.7.9:

A BibTeX entry for LaTeX users is

  @TechReport{,
    title = {smwrQW--An R Package for Managing and Analyzing Water-Quality Data, Version 0.7.9},
    author = {Dave Lorenz},
    institution = {U.S. Geological Survey},
    series = {Open File report},
    year = {in preparation},
  }