@Article{GHS:JACM56-3,
  author    = {Martin Grohe and Andr{\'e} Hernich and Nicole Schweikardt},
  title     = {Lower Bounds for Processing Data with Few Random Accesses
               to External Memory},
  year      = {2009},
  month     = {May},
  journal   = {J.\ ACM},
  volume    = {56},
  number    = {3},
  pages     = {Article 12},
  note      = {Full version of PODS 2005 and PODS 2006 papers.}
}