@article {LieSay05,
    AUTHOR = {Liesen, J{\"o}rg and Saylor, Paul E.},
     TITLE = {Orthogonal {H}essenberg reduction and orthogonal
              {K}rylov subspace bases},
   JOURNAL = {SIAM J. Numer. Anal.},
  FJOURNAL = {SIAM Journal on Numerical Analysis},
    VOLUME = {42},
      YEAR = {2005},
    NUMBER = {5},
     PAGES = {2148--2158},
}