\begin{thebibliography}{1}

\bibitem{nasa_voyager}
Voyager - mission overview.

\bibitem{jehnBepi}
Rüdiger Jehn, Daniel García~Yárnoz, Johannes Schoenmaekers, and Vicente
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\newblock Trajectory design for bepicolombo based on navigation requirements.
\newblock {\em Journal of Aerospace Engineering, Sciences and Applications},
  4:1--9, 01 2012.

\end{thebibliography}