"Using Abbreviations or Symbols" "Using Abbreviations or Symbols" "Using Abbreviations or Symbols" http://www.unc.edu/~rowlett/units/symbol.html "Using Abbreviations or Symbols" "Using Abbreviations or Symbols" http://www.unc.edu/~rowlett/units/symbol.html "Using Abbreviations or Symbols" http://www.unc.edu/~rowlett/units/symbol.html "Using Abbreviations or Symbols" "Using Abbreviations or Symbols" "Using Abbreviations or Symbols" http://www.unc.edu/~rowlett/units/symbol.html http://www.unc.edu/~rowlett/units/symbol.html "Using Abbreviations or Symbols" "Using Abbreviations or Symbols" [www.unc.edu]