LeBlanc, Mark D., and Betsey Dexter Dyer. "Phrasing Questions by Writing Algorithms." Perl for Exploring DNA. : Oxford University Press, 2007-08-23. Oxford Scholarship Online. 2010-04-01. Date Accessed 22 May. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195305890.001.0001/acprof-9780195305890-chapter-11>.
LeBlanc, M., & Dexter Dyer, B.(2007-08-23). Phrasing Questions by Writing Algorithms. In Perl for Exploring DNA. : Oxford University Press. Retrieved 22 May. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195305890.001.0001/acprof-9780195305890-chapter-11.
LeBlanc, Mark D., and Betsey Dexter Dyer. "Phrasing Questions by Writing Algorithms." In Perl for Exploring DNA. : Oxford University Press, 2007-08-23. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195305890.001.0001/acprof-9780195305890-chapter-11.
LeBlanc MD, Dexter Dyer B. Phrasing Questions by Writing Algorithms. In: LeBlanc MD, Dyer BD. Perl for Exploring DNA. Oxford University Press; 2007. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780195305890.001.0001/acprof-9780195305890-chapter-11. Accessed May 22, 2013.