引用问题

Question

我正在使用 IEEE 模板，但遇到最后一个 BibTex 引用发生偏移的问题

有人怀疑这个问题

\begin{document}
\bibliographystyle{IEEEtran} 
\bibliography{literatur}
    @ELECTRONIC{7,
  title = {{Simulation of Urban MObility (Sumo)}},
  url = {http://sumo.dlr.de/wiki/Main_Page},
  owner = {},
  timestamp = {2015.06.15}
}

@ELECTRONIC{8,
  title = {{Microsoft Excel}},
  url = {https://products.office.com},
  owner = {},
  timestamp = {2015.06.15}
}
\end{document}