2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/214433Two different methods of the covariant relativistic separable kernel construction in the Bethe-Salpeter approach are considered. One of them leads in the center-of-mass system of two particles to the quasipotential equation. The constructed 4-dimensional covariant functions are used to reproduce neutron-proton phase shifts for total angular momenta $J=0,1$. Obtained results are compared with other model calculations.10 pages, 5 figures; Proceedings of the conference: The XVIII International Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics and Quantum Chromodynamics", 2006; published in 2008Nuclear Theorytext