Oster, H., Werner, C., Magnone, M. C., Mayser, H., Feil, R., Seeliger, M. W., et al. (2003). cGMP-Dependent Protein Kinase II Modulates mPer1 and mPer2 Gene Induction and Influences Phase Shifts of the Circadian Clock. Current Biology, 13(9), 725-733. Retrieved from http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6VRT-48GV9DX-P-1&_cdi=6243&_user=38661&_pii=S0960982203002525&_orig=search&_coverDate=04%2F29%2F2003&_sk=999869990&view=c&wchp=dGLzVzb-zSkzk&md5=f40a551703fa923d504dd157b9b22198&ie=/sdarticle.pdf.