Comment on "Sixth-Order Vacuum-Polarization Contribution to the Lamb Shift of Muonic Hydrogen" by T. Kinoshita and M. Nio, Phys. Rev. Lett. 82, 3240 (1999)

In the comment we discuss an additional term to the ${\alpha }^3$ correction to the Lamb shift, which was missed in the calculation by Kinoshita and Nio (Phys. Rev. Lett. 82, 3240 (1999)).