1. Boyd, Brian. ?Common Words in Titus Andronicus: the Presence of Peele.?Notes and Queries, 240(1995), 300(September).
2. Campbell, Oscar James and Edward G. Quinn, Eds. The Reader's Encyclopedia of Shakespeare. New York: Thomas Y Crowell, 1966.
3. Douglass, Melinda.Applications of Genetic Algorithm. Claremont, California: Claremont McKenna College Senior Thesis, 1993.
4. Efron, Brad, and Thisted, Ronald. ?Estimating the Number of Unseen Species: How Many Words Did Shakespeare Know??Biometrika, 63(1976), 435.
5. Elliott, Ward and Robert Valenza. ?A Touchstone for the Bard.?Computers and the Humanities 25 (1991), 199.