Fabiano, E., Groenhof, G., & Thiel, W. (2008). Approximate switching algorithms for trajectory surface hopping. Chemical Physics, 351(1-3), 111-116. Retrieved from http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6TFM-4SB7TYJ-2-7&_cdi=5230&_user=38661&_orig=browse&_coverDate=07%2F03%2F2008&_sk=996489998&view=c&wchp=dGLbVlz-zSkWA&md5=542f59f6c5b04804e4cb95c4273ed979&ie=/sdarticle.pdf.