@Article{Adams-03a,
  author =   {Adams, M.~F.},
  title =   {Algebraic multrigrid methods for constrained linear systems with applications to contact problems in solid mechanics},
  journal =   {Numerical Linear Algebra with Applications},
  year =   {2004},
  volume =   {11},
  number =   {2-3},
  pages =   {141-153}
}