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This is a citation for which 5\deg the citation should be known \cite{known}.
We follow this with an unknown citation \cite{unknown}.

To test various combinations we need to cite more than one author.  To this
end, I cite two known authors \cite{known,known2}.  This might include one
known and one unknown \cite{unknown,known}.  Another bizarre case might be
one known, one unknown and another known \cite{known,unknown,known2}.

Need to have a test for \verb#\cite# commands that span multiple lines \cite{
known,%
%  very long comment that has some utility
known2} (which has two comment lines in a row!) and one final test \cite{%
known, %
known2%  some jabbering
}.

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