@article{etna_vol20_pp75-85,
  author  = {Na Li and Yousef Saad},
  title   = {Crout versions of ILU factorization with pivoting for sparse symmetric matrices},
  journal = {Electron. Trans. Numer. Anal.},
  volume  = {20},
  year    = {2005},
  pages   = {75--85},
}