\begin{figure}[!ht]
  \centering
  \begin{subfigure}[b]{0.23\linewidth}
    \includegraphics[width=\linewidth]{Bilder/ContendBasedFlow.jpg}
    \caption{\textit{Content-Based}.}
    \label{fig:cb}
  \end{subfigure}
  \begin{subfigure}[b]{0.23\linewidth}
    \includegraphics[width=\linewidth]{Bilder/CollaborativeFlow.jpg}
    \caption{\textit{Collaborative-Filtering}.}
    \label{fig:cf}
  \end{subfigure}
  \caption{Overview of \textit{content-based} (left) and \textit{collaborative-filtering} (right) \textit{recommender systems}. \textit{Content-based recommender systems} work via \textit{feature vectors}. In contrast, \textit{collaborative filtering recommender systems} work over \textit{neighborhoods}.}
  \label{fig:cbcf}
\end{figure}