@article{etna_vol26_pp82-102,
  author  = {Drahoslava Janovsk\'a and Gerhard Opfer},
  title   = {Computing quaternionic roots by Newton's method},
  journal = {Electron. Trans. Numer. Anal.},
  volume  = {26},
  year    = {2007},
  pages   = {82--102},
}