In Leptons: Classes, Properties and Interactions, the authors develop a model to calculate the masses of charged leptons by quantifying the electrostatic field generated by these particles. This model is extended to weak and strong interactions in order to calculate the masses of all elementary fermions.Next, by taking the SU(2) group of weak interactions in the presence of Electric Charge Swap-symmetry as a starting point, this compilation show that ordinary and non-regular leptons are related by the ECS-rotational SO(3) group. By considering the ECS-Hamiltonian quaternions for leptons, the authors find that the SU(5) Grand Unified Theory originates from the image of normalized quaternions group N(Q8) under the ECS-rotations.The differential cross-section corresponding to a dispersion process in the context of the 331RHν model is calculated in order to use the results in terrestrial and astrophysical experiments. The differential cross-section is written in terms of the mass of the new gauge boson Z′, the mixing angle, the magnetic moment of the neutrino, and the charge radius.In closing, the authors obtain analytical expressions for the total cross section of the process e+e− τ+τ−γ in the context of the B-L model. The total cross section is analyzed in terms of themass of the new gauge boson Z′, the mixing angle θ′ of the B-L model, the magneticmoment and the electric dipole moment of the τ -lepton.