19 only (exchange by only one Breit and two Coulomb photons), whereas we calculated so called “iterated” Breit interaction (exchange by two Breit and one Coulomb photons, and by three Breit photons). It should be also mentioned that Yerokhin et al. [13] included the negative- energy contribution for the correction considered. However, this contribution is relatively small. As comparing to Andreev et al. [51], a distinct deviation is found. Most probably, as indicated in Ref. [13], it is due to an overestimation of the contribution induced by two Breit and one Coulomb photon exchange in Ref. [51]. The results with this contribution subtracted are marked by an asterisk in the table. They are much closer to our results. In Table VII we collect all the electronic-structure contributions to the transition energies and compare our results with those by other authors. For comparison we chose the most recent data from Ref. [13], which are in reasonable agreement with others calculations. Only for light ions with small Z = 3 − 15, where the correlation effects are large compared to the relativistic contributions, results of other works (without QED effects) are also presented. The column labeled “Dirac” contains the energy value obtained from the Dirac equation with an extended nucleus. The Fermi nuclear charge distribution was employed. Except for uranium, the root-mean-square (rms) radii were taken from Ref. [56]. In case of uranium, we use the rms value from Ref. [16] and take into account the nuclear deformation effect (see Ref. [16] for details). The two-photon exchange correction is evaluated within the framework of QED, following our previous investigations [8, 11]. The uncertainty given is due to the higher-order interelectronic interaction only. In addition to a different treatment of the Breit interaction in the present work and in Ref. [13] (see the related discussion above), we note some difference in evaluation of the QED part of the two-photon exchange contribution. In our work it was calculated with the pure Coulomb potential while in Ref. [13] a local screening potential was employed. We remind also the reader that, in accordance with our definition of the electronic-structure part, the values in Table VII are given in the nonrecoil limit.