Abstract
A realization is given, in terms of Dirac matrices and suitable SL(2,c) generators, of Gel'fand-Yaglom matrices associated with the simplest parity-invariant wave equations for particles with half-odd-integral spin. Commutation and anti-commutation relations for these matrices are thereby derived, replacing those given previously by Lorente, Huddleston and Roman (see abstr. A8608 of 1974) which are shown to be incorrect.