AvigadS97'

@article{DBLP:journals/bsl/AvigadS97,
  author    = {Jeremy Avigad and
               Richard Sommer},
  title     = {A model-theoretic approach to ordinal analysis},
  journal   = {Bulletin of Symbolic Logic},
  volume    = {3},
  number    = {1},
  year      = {1997},
  pages     = {17-52},
  ee        = {http://www.math.ucla.edu/$\sim$asl/bsl/0301/0301-002.ps},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}