“…Note that our quadratic model also gives the two signs of the energy that, as shown in [12], are related to the propagation of (++) and (−−) fermionic states. In that equation, the (+−) and (−+) states are completely suppressed, while, in another (similar) relativistic model [11], they only appear as closed-channel, virtual states. In this way, our equation and the two models cited above do not admit spurious solutions with M = 0, avoiding the socalled continuum dissolution problem, discussed, for example, in Ref.…”