%\documentclass[ACO]{baltzer}
%\documentclass[seceqn,secthm,ACO]{baltzer}
%\documentclass[seceqn,secthm,WN,twocolumn,10pt]{baltzer}
\documentclass{baltzer}
%\usepackage{}
%%\renewcommand{\baselinestretch}{1} %optional
%% NEWCOMMANDS, NEWENVIRONMENTS:
%
%\volume{7}       %optional
%\pubyear{1997}   %optional
%\firstpage{601}  %optional
%\lastpage{610}   %optional
%
\begin{document}
\begin{frontmatter}
%
%\pretitle{}                  %   e.g.: \pretitle{Guide}
\title{...\thanks{...}}       %   \thanks{} is optional
%\subtitle{}                  %   e.g.: \subtitle{Dedicated ...}
\author[A]{...\thanks{...}}      %   \thanks{} is optional
\author[B]{...}
\address[A]{...\email{...}}   %   \email{} is optional
\address[B]{...}
\runningauthor{}
\runningtitle{}
% HISTORY:    %% HISTORY is optional
%\received{19 February 1997}
%\revised{}
%\accepted{}
%\dedicated{}
%\presented{}
%
\begin{abstract}  % abstract goes here
\end{abstract}
%
\begin{keywords}  % keywords go here
\end{keywords}
\classification{} % AMS classif. codes go here
\end{frontmatter}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%\def's
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%*************** Text entry area *************
\section{}

%%%********** End of text entry ****************
\begin{thebibliography}{00} %{00} for numbered bibliography

\bibitem{A1}

\bibitem{A2}

\bibitem{B1}

\end{thebibliography}
%
\end{document}