  One of us quant-ph/0206077 (Nucl. Phys. B, 1970, 21, 321) has shown that for
the particle with zero mass and spin s=1/2 there are three types of
two-component equations (or one four-component equation with three different
subsidiary conditions) which differ from one another by P, T and C properties.
One of these equations is the two-component Weyl equation. In this note we give
two other relativistic invariant equations.
