@article {LiePar08,
    AUTHOR = {Liesen, J{\"o}rg and Parlett, Beresford N.},
     TITLE = {On nonsymmetric saddle point matrices that allow conjugate gradient iterations},
   JOURNAL = {Numer. Math.},
  FJOURNAL = {Numerische Mathematik},
    VOLUME = {108},
      YEAR = {2008},
    NUMBER = {4},
     PAGES = {605--624},
}