One More Analytic Result for $\alpha^{2}(Z\alpha)^{5}m$ Correction to   the Lamb Shift
  The analytic result for the radiative correction of order $\alpha^{2}(Z\alpha)^{5}m$ to the Lamb shift connected with a polarization insertion in one of the two external Coulomb lines is obtained. This correction arises from a gauge invariant set of diagrams which contain, besides the polarization insertion in the Coulomb leg, all one-loop radiative photon insertions in the electron line with two external Coulomb lines. 
Michael I. Eides (Petersburg Nuclear Physics Institute, Russia, and   Pennsylvania State University, USA), Howard Grotch (Pe...