@article{Hajja05,
  title = {Copositive Symmetric Cubic Forms},
  author = {Mowaffaq Hajja},
  year = {2005},
  url = {http://www.jstor.org/stable/30037498},
  researchr = {https://researchr.org/publication/Hajja05},
  cites = {0},
  citedby = {0},
  journal = {The American Mathematical Monthly},
  volume = {112},
  number = {5},
  pages = {462-466},
}