@article{payaro:TIT09,
  title = "{Hessian and concavity of mutual information, differential entropy, and entropy power in linear vector Gaussian channels}",
  author = "M.~Payar\'o and D.~P.~Palomar",
  journal = "{IEEE} Trans. on Information Theory",
  volume = "55",
  number = "8",
  month = "Aug.",
  pages = "3613 - 3628",
  year = {2009}
}