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old Integral:
\begin{equation}
  \label{eq:new:2}
  \int_{a+1} A^{a} dx = \sum\limits_a^b \lambda  \varrho 
\end{equation}
\begin{equation}
  \label{eq:klaus-t15sep:6}
  \int\limits_a^b \quad \qquad \qquad \qquad 
\end{equation}
\begin{equation}
  \int_a
\end{equation}
\begin{equation}
  \label{eq:new:1}
  \int_1 y_{n+1} \int_{n} \quad 
\end{equation}
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