The review article by W Nakel and C. T. Whelan you refer to do indeed tackle the relativistic regime but at the expense of a huge amount of numerical work. So, we think that presenting for the first time a work that incorporates fully analytical results and QED formalism is interesting to the scientific community. The work of W Nakel and C. T. Whelan is devoted to study heavy atoms but Our work is aimed to study analytically the hydrogen atom, we believe that such a comparison is impossible. Another difference that makes comparison difficult is that the work of W Nakel and C. T. Whelan uses coplanar asymmetric geometry while in our work we use coplanar symmetric geometry.
· Line 108: don’t capitalize “triple” · Line 112 and caption for Table I: insert “the” before “TDCS: and “peaks” and change “peak’s” to “peak” without italics · Line 115: delete “for positron impact” at end of sentence.