@BOOK{F1,
  SHORTHAND         = {\emph{A}},
  SORTSHORTHAND     = {A},
  AUTHOR	          = {John Doe},
  TITLE		          = {The Fullness of Times},
  YEAR		          = {1995},
}

% Duplicate key. Should be reported via a warning
@MISC{F1,
  AUTHOR	          = {Frank Frill},
  TITLE		          = {Dresses for Gentlemen},
  YEAR		          = {1997},
}

% Mismatched cased key. Should be reported via a warning
@BOOK{f1,
  AUTHOR	          = {Someone Else},
  TITLE		          = {The Case of the Duplicitous Duplicate},
  YEAR		          = {1996},
}

@MISC{c1,
 AUTHOR = {Benny Balgreen},
 TITLE  = {Names We Invent},
 YEAR   = {1900}
}