Williamson, Jon. "LANGUAGE CHANGE." Bayesian Nets and Causality: Philosophical and Computational Foundations. : Oxford University Press, 2004-12-23. Oxford Scholarship Online. 2007-09-01. Date Accessed 18 Jun. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780198530794.001.0001/acprof-9780198530794-chapter-12>.
Williamson, J.(2004-12-23). LANGUAGE CHANGE. In Bayesian Nets and Causality: Philosophical and Computational Foundations. : Oxford University Press. Retrieved 18 Jun. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780198530794.001.0001/acprof-9780198530794-chapter-12.
Williamson, Jon. "LANGUAGE CHANGE." In Bayesian Nets and Causality: Philosophical and Computational Foundations. : Oxford University Press, 2004-12-23. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780198530794.001.0001/acprof-9780198530794-chapter-12.
Williamson J. LANGUAGE CHANGE. In: Williamson J. Bayesian Nets and Causality: Philosophical and Computational Foundations. Oxford University Press; 2004. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780198530794.001.0001/acprof-9780198530794-chapter-12. Accessed June 18, 2013.