@article {MR3034309,
    AUTHOR = {Du, Xiuhong and Sarkis, Marcus and Schaerer, Christian E. and
              Szyld, Daniel B.},
     TITLE = {Inexact and truncated parareal-in-time {K}rylov subspace
              methods for parabolic optimal control problems},
   JOURNAL = {Electron. Trans. Numer. Anal.},
  FJOURNAL = {Electronic Transactions on Numerical Analysis},
    VOLUME = {40},
      YEAR = {2013},
     PAGES = {36--57},
      ISSN = {1068-9613},
   MRCLASS = {65F10 (49M25)},
  MRNUMBER = {3034309},
}