Birkhoff75'

BibTeX

@article{DBLP:journals/cacm/Birkhoff75,
  author    = {Garrett Birkhoff},
  title     = {Two Hadamard Numbers for Matrices},
  journal   = {Commun. ACM},
  volume    = {18},
  number    = {1},
  year      = {1975},
  pages     = {25-29},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}