@article{gregory81,
  address = {New York, NY},
  author = {de Caen, D. and Gregory, D. A.},
  interhash = {48219154b23d9f15a5fb30e20788a117},
  intrahash = {15e03da7f049d633a94ed3c31f5df318},
  journal = {Linear Algebra and its Applications},
  pages = {119-134},
  publisher = {American Elsevier Publications},
  title = {Primes in the Semigroup of Boolean Matrices},
  volume = 37,
  year = 1981
}