[en] In the case of two interacting spinor fields with equal masses the first version of the Logunov-Tavkhelidze quasipotential approach is used to construct the quasipotential. The second-order term in the perturbation theory in Coulomb gauge is computer. A Dirac four-component term for the direct and exchange interaction particles is obtained. A two-component Pauli-form for the leading term of the quasipotential is also worked out in nonrelativistic limit for direct interaction the exact structure of the Breit potentials is obtained, without additional terms explicity depending on the energy. For the exchange interaction the same result has been obtained previously using different methods