A new approach to the representation theory of the symmetric groups. IV.   $ \Bbb Z_{2}$-graded groups and algebras
  We start with definitions of the general notions of the theory of $\Bbb Z_{2}$-graded algebras. Then we consider theory of inductive families of $\Bbb Z_{2}$-graded semisimple finite-dimensional algebras and its representations in the spirit of approach of the papers \cite{VO,OV} to representation theory of symmetric groups. The main example is the classical - theory of the projective representations of symmetric groups. 
A.M.Vershik, A.N.Sergeev