Albrecht, U., & Oster, H. (2001). The circadian clock and behavior. Behavioural Brain Research, 125(1-2), 89-91. Retrieved from http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6SYP-448YK1K-F-5&_cdi=4840&_user=38661&_pii=S0166432801002881&_origin=search&_coverDate=11%2F08%2F2001&_sk=998749998&view=c&wchp=dGLbVzW-zSkzS&md5=b101caa53ef4b0f412cabf2dacaffb85&ie=/sdarticle.pdf.