Authors: Helen K White; Pen-Yuan Hsing; Walter Cho; Timothy M Shank; Erik E Cordes; Andrea M Quattrini; Robert K Nelson; Richard Camilli; Amanda W J Demopoulos; Christopher R German; James M Brooks; Harry H Roberts; William Shedd; Christopher M Reddy; Charles R Fisher Journal: Proc Natl Acad Sci U S A Date: 2012-03-27 Impact factor: 11.205