@article{Nor91,
	title = {Techniques for Automatic Memoization with Applications to
  Context-Free Parsing},
	author = {Peter Norvig},
	journal = {Computational Linguistics},
	number = {1},
	pages = {91--98},
	volume = {17},
	year = {1991},
	biburl = {http://www.bibsonomy.org/bibtex/210b64331eb8c5da961d9b9669084b53b/nlp},
	keywords = {2000 book nlp }
}