\documentclass{annalife}

\begin{document}
\title{Paper Title}
\author{\uppercase{P.~Autore1}\istituto{Department, University, address, e-mail.}
   \and \uppercase{Q.~Autore2}\istituto{Department, University, address, e-mail.}
}
\authorhead{\lowercase{P.~Autore1 - Q.~Autore2}}
\titlehead{\lowercase{Paper Title, eventually shortened}}
\date{}
\maketitle
%
\begin{sunto}
Testo del sunto in italiano.
\end{sunto}
\begin{abstract}
Paper abstract in English.
\end{abstract}
%
\section{Introduction} % Titolo della prima sezione

In this work...

\section{Section Title}

Consider the equation (see e.g. \cite{AutoreP-AutoreS-AutoreT-2001}):
\begin{equation}
  a+b=100
  \label{eq:sum}
\end{equation}

\begin{Defi}
We call $\Omega$ the set...
\end{Defi}

\begin{Theo}
\label{firstth}
Suppose the set $\Omega$ as in \cite[pag. 35]{AutoreQ-1990}...
\end{Theo}

\section{Section Title}

The problem is...
%
\begin{Lem}
If the set $\Omega$ is...
\end{Lem}
\Proof
From (\ref{eq:sum}) and Theorem \ref{firstth} we have... \par
This completes the proof.
\qed

\section{Conclusion}

Our conclusions are...

\begin{thebibliography}{2}

\bibitem{AutoreP-AutoreS-AutoreT-2001}
\BY{P.~AAutore - S.~CAutore - T.~DAutore}, 
\IN{Paper title},
\JOUR{Journal name},
\VOL{99}
\YEAR{2001},
\PAGES{199--200}.

\bibitem{AutoreQ-1990}
\BY{Q.~BAutore}, 
\IN{Book title},
\JOUR{Editorial information}
\YEAR{1990}.

\end{thebibliography}

\end{document}

