# Relativistic correction to Coulomb Potential in SQED

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Homework Statement:
Obtain the relativictic lower order correction to the Coulombian potential
Relevant Equations:
Those ones that are in the appended photo
I have derived the Coulombian potential as an effective potential between two spinless charged particle taking the non-relativitic approach on the scattering amplitude obtained in terms of the Feynman rules in SQED.
The scattering amplitudes are:

I'm using the gauge in which xi = 1.
How could I obtain the relativistic lower order correction of the Coulombian potential using those amplitudes??