@article{JMLR:v10:xu09a,
  author  = {Yuesheng Xu and Haizhang Zhang},
  title   = {Refinement of Reproducing Kernels},
  journal = {Journal of Machine Learning Research},
  year    = {2009},
  volume  = {10},
  number  = {4},
  pages   = {107--140},
  url     = {http://jmlr.org/papers/v10/xu09a.html}
}