natbib-expansion.tex

\DeclareRobustCommand\citet
   {\begingroup\NAT@swafalse\let\NAT@ctype\z@\NAT@partrue
     \@ifstar{\NAT@fulltrue\NAT@citetp}{\NAT@fullfalse\NAT@citetp}}

\DeclareRobustCommand\citep
  {\begingroup\NAT@swatrue\let\NAT@ctype\z@\NAT@partrue
    \@ifstar{\NAT@fulltrue\NAT@citetp}{\NAT@fullfalse\NAT@citetp}}

\newcommand\NAT@citetp{\@ifnextchar[{\NAT@@citetp}{\NAT@@citetp[]}}

\def\NAT@@citetp[#1]{\@ifnextchar[{\@citex[#1]}{\@citex[][#1]}}

% \NAT@numbersfalse, by default
\let\@citex\NAT@citex



\newcommand\NAT@cite[3]{
  \ifNAT@swa
    \NAT@@open
    \if*#2*\else#2\NAT@spacechar\fi
    #1
    \if*#3*\else\NAT@cmt#3\fi
    \NAT@@close
  \else
    #1
  \fi
  \endgroup}



% \bibcite
%   {betts2005aging}
%   {{10}{2005}{{Betts {和} Taylor}}{{Betts and Taylor}}}

\renewcommand\bibcite[2]{%
 \@ifundefined{b@#1\@extra@binfo}{\relax}{%
   \NAT@citemultiple
   \PackageWarningNoLine{natbib}{Citation `#1' multiply defined}%
 }%
 \global\@namedef{b@#1\@extra@binfo}{#2}%
}%