Machery, Edouard. "Categorization and Concept Learning." Doing without Concepts. : Oxford University Press, 2009-03-19. Oxford Scholarship Online. 2009-05-01. Date Accessed 19 Jun. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195306880.001.0001/acprof-9780195306880-chapter-7>.
Machery, E.(2009-03-19). Categorization and Concept Learning. In Doing without Concepts. : Oxford University Press. Retrieved 19 Jun. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195306880.001.0001/acprof-9780195306880-chapter-7.
Machery, Edouard. "Categorization and Concept Learning." In Doing without Concepts. : Oxford University Press, 2009-03-19. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195306880.001.0001/acprof-9780195306880-chapter-7.
Machery E. Categorization and Concept Learning. In: Machery E. Doing without Concepts. Oxford University Press; 2009. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195306880.001.0001/acprof-9780195306880-chapter-7. Accessed June 19, 2013.