@book{knuth2011combinatorial,
  asin = {0201038048},
  author = {Knuth, Donald E.},
  dewey = {001.642},
  ean = {9780201038040},
  interhash = {276f5451e5ece797ff2c247aaa2866a8},
  intrahash = {481baec64f095b2555e780614e5c8f13},
  isbn = {0201038048},
  month = jan,
  publisher = {Addison-Wesley Professional},
  series = {The Art of Computer Programming},
  title = {Combinatorial Algorithms},
  url = {http://www.amazon.com/Art-Computer-Programming-Combinatorial-Algorithms/dp/0201038048/ref=sr_1_1/179-7432054-1264222?ie=UTF8&s=books&qid=1298901523&sr=8-1},
  volume = {4A},
  year = 2011
}

@book{knuth1998art2,
  address = {Boston, MA, USA},
  author = {Knuth, Donald E.},
  edition = {2nd},
  interhash = {f8866d240e847372a483fdc7bd741523},
  intrahash = {bbcd4d56e619911172e571d36bb28f3b},
  isbn = {0-201-89685-0},
  publisher = {Addison-Wesley Longman Publishing Co.},
  title = {The art of computer programming},
  url = {http://portal.acm.org/citation.cfm?id=270146},
  volume = 3,
  year = 1998
}