@article{greiner2015very,
  author = {Greiner, J. and Mazzali, P.-A. and Kann, D.-A. and Kr{\"u}hler, T. and Pian, E. and Filgas, R.},
  title = {A very luminous magnetar-powered supernova associated with an ultra-long gamma-ray burst},
  journal = {Nature},
  publisher = {Springer Science and Business Media LLC},
  volume = {523},
  number = {7559},
  pages = {189--192},
  year = {2015},
  doi = {10.1038/nature14579},
  issn = {0028-0836}
}