%
% own commands
%

%double empty page
\newcommand \myemptypage {
    \clearpage
    \thispagestyle{empty}
    \null
    \cleardoublepage
}

%create abstract environment that is not available in latex book style
\newcommand\abstractname{Abstract}
\newenvironment{abstract}{%
    \begin{center}%
        \normalfont\Large\bfseries \abstractname
    \end{center}%
    \it%
    }
    {}