\documentclass{article} \begin{document} \section{Radiation Damage1} This is a test1. \subsection{Radiation Damage2}\label{a2} This is a test2. \subsubsection{Radiation Damage3} This is a test3. It is mentioned in section~\ref{a2} but more in appendix~\ref{bbb}. \section{Radiation Damage1} This is a test1. \section{Radiation Damage1} This is a test1. \appendix \section{Radiation Damage4}\label{bbb} This is a test1. \section{Radiation Damage5} This is a test1. \end{document}