@Article{Caliari:2008:APL,
  author =       "Marco Caliari and Stefano De Marchi and Marco Vianello ",
  title =        "Algorithm 886: {Padua2D}: {Lagrange} Interpolation at {Padua} Points on Bivariate Domains",
  journal =      "{ACM} Transactions on Mathematical Software",
  volume =       "35",
  number =       "3",
  month =        oct,
  year =         "2008",
  pages =        "21:1--21:11",
  URL =          "http://doi.acm.org/10.1145/1391989.1391994",
  abstract =     "We present a stable and efficient Fortran implementation of polynomial interpolation at the ``Padua points'' 
                 on the square $[-1,1]^2$. These points are unisolvent and their Lebesgue constant has minimal order of growth 
                 (log square of the degree). The algorithm is based on the representation of the Lagrange interpolation formula 
                 in a suitable orthogonal basis, and takes advantage of a new matrix formulation together with the 
                 machine-specific optimized BLAS subroutine DGEMM for the matrix-matrix product. Extension to interpolation on 
                 rectangles, triangles and ellipses is also described.",
}