SBML file used for the systems model described in our paper (see below) can be downloaded from http://www.seas.upenn.edu/~biophys/dissemination/egfr_diff_phos.xml Y. Liu§, J. Purvis§, A. Shih, J. Weinstein, N. Agrawal, R. Radhakrishnan, “A multiscale computational approach to dissect early events in the Erb family receptor mediated activation, preferential signaling, and relevance to oncogenic transformations”, 2007, Annals of Biomedical Engineering, in press, DOI: 10.1007/s10439-006-9251-0; § these authors contributed equally. The paper can be found at http://www.seas.upenn.edu/~biophys/cv_files/abme_print.pdf