Zhang C-T. The e-Index, Complementing the h-Index for Excess Citations. PLoS ONE 2009;4(5): e5429.
A new indicator is here proposed: the e-index. It is a necessary h-index complement since it represents the ignored excess citations. Therefore, for accurate and fair comparisons, it is necessary to use the e-index together with the h-index, which are independent of each other.
The e-index is a useful measure to compare group of researchers having the same h-index or to evaluate highly cited scientists.