@incollection {MR1312384,
    AUTHOR = {Sarkis, Marcus},
     TITLE = {Multilevel methods for {$P\sb 1$} nonconforming finite
              elements and discontinuous coefficients in three dimensions},
 BOOKTITLE = {Domain decomposition methods in scientific and engineering
              computing ({U}niversity {P}ark, {PA}, 1993)},
    SERIES = {Contemp. Math.},
    VOLUME = {180},
     PAGES = {119--124},
 PUBLISHER = {Amer. Math. Soc.},
   ADDRESS = {Providence, RI},
      YEAR = {1994},
   MRCLASS = {65N55 (65F10 65F35 65N30)},
  MRNUMBER = {1312384},
}