1\ProvidesPackage{natbib}
2\input{natbib-common.hva}
3\renewcommand{\@NAT@os}{{\@nostyle\@print{<sup>}}}
4\renewcommand{\@NAT@cs}{{\@nostyle\@print{</sup>}}}
5\renewcommand{\@biblabel}[1]
6{\@locname{#1}{\NAT@bibread{#1}\purple\NAT@format@item{#1}{\NAT@num}{\NAT@auth}{\NAT@year}}}
7\newcommand{\NAT@fmt}[3]
8  {\def\@tmp{#2}\ifx\@tmp\@empty{}???\else\NAT@format@cite{#2}{#3}{#1}\fi}
9\renewcommand{\@bibref}[3]
10{\ifciteindex\@locnameref{\NAT@index{#1}}{#1}{\NAT@fmt{#1}{#2}{#3}}%
11\else\@locref{#1}{\NAT@fmt{#1}{#2}{#3}}\fi}
12