Goldberg, Deborah T.. AP biology. 3rd ed. Hauppauge, N.Y.: Barron's Educational Series, Inc., 20102007. Print.
Greenberg, Neil. "PHYSIOLOGY - CNS notes - Positive feedback." PHYSIOLOGY - CNS notes - Positive feedback. GREENBERG, n.d. Web. 20 Apr. 2014. <https://notes.utk.edu/bio/greenberg.nsf/daff0e5940a0d14285257015006e1933/aea6b52b645de868852572200079e95f?OpenDocument>.
"Homeostasis. Positive Feedback Control of Labor.." Homeostasis. Positive Feedback Control of Labor.. N.p., n.d. Web. 20 Apr. 2014. <http://www.johnwiley.net.au/highered/interactions/media/Foundations/content/Foundations/homeo4a/bot.htm>.
"Parts of the Brain - Intro to Psychology Video." Education Portal. N.p., n.d. Web. 21 Apr. 2014. <http://education-portal.com/academy/lesson/parts-of-the-brain.html#lesson>.
Reece, Jane B. Campbell Biology. 9th ed. San Francisco: Pearson Education, 2011. Mastering Biology. Pearson Education. Web. 20 Apr. 2014.
"THE NERVOUS SYSTEM." the nervous system. N.p., n.d. Web. 21 Apr. 2014. <http://www2.estrellamountain.edu/faculty/farabee/biobk/biobooknerv.html>.
Greenberg, Neil. "PHYSIOLOGY - CNS notes - Positive feedback." PHYSIOLOGY - CNS notes - Positive feedback. GREENBERG, n.d. Web. 20 Apr. 2014. <https://notes.utk.edu/bio/greenberg.nsf/daff0e5940a0d14285257015006e1933/aea6b52b645de868852572200079e95f?OpenDocument>.
"Homeostasis. Positive Feedback Control of Labor.." Homeostasis. Positive Feedback Control of Labor.. N.p., n.d. Web. 20 Apr. 2014. <http://www.johnwiley.net.au/highered/interactions/media/Foundations/content/Foundations/homeo4a/bot.htm>.
"Parts of the Brain - Intro to Psychology Video." Education Portal. N.p., n.d. Web. 21 Apr. 2014. <http://education-portal.com/academy/lesson/parts-of-the-brain.html#lesson>.
Reece, Jane B. Campbell Biology. 9th ed. San Francisco: Pearson Education, 2011. Mastering Biology. Pearson Education. Web. 20 Apr. 2014.
"THE NERVOUS SYSTEM." the nervous system. N.p., n.d. Web. 21 Apr. 2014. <http://www2.estrellamountain.edu/faculty/farabee/biobk/biobooknerv.html>.