QED Calculation of E1M1 and E1E2 Transition Probabilities in   One-Electron Ions with Arbitrary Nuclear Charge
  The quantum electrodynamical theory of the two-photon transitions in hydrogenlike ions is presented. The emission probability for 2s1/2 -> 2E1+1s1/2 transitions is calculated and compared to the results of the previous calculations. The emission probabilities 2p12 -> E1E2+1s1/2 and 2p1/2 -> E1M1+1s1/2 are also calculated for the nuclear charge Z values 1-100. This is the first calculation of the two latter probabilities. The results are given in two different gauges. 
L. N. Labzowsky, A. V. Shonin, D. A. Solovyev