Relativistic multirank interaction kernels of the neutron-proton system
  The multirank separable kernels of the neutron-proton interaction for uncoupled $S$ and $P$ partial waves (with the total angular momentum $J$=0,1) are proposed. Two different methods of a relativistic generalization of initially nonrelativistic form factors parametrizing the kernel are considered. Using the constructed kernels the experimental data for phase shifts in the elastic neutron-proton scattering for the laboratory energy up to 3 GeV and low-energy parameters are described. The comparison of our results with other model calculations are presented. 
S.G. Bondarenko, V.V. Burov, W.-Y. Pauchy Hwang, E.P. Rogochaya