  The structure of 29-dimensional extended real Clifford-Dirac algebra, which
has been introduced in our paper Phys. Lett. A, 2011, 375, 2479, is considered
in brief. Using this algebra, the property of Fermi-Bose duality of the Dirac
equation with nonzero mass is proved. It means that Dirac equation can describe
not only the fermionic but also the bosonic states. The proof of our assertion
based on the examples of bosonic symmetries, solutions and conservation laws is
given. Some statistical aspects of the spinor field Fermi-Bose duality are
discussed.
