On weak generalized stability and (c,d)-pseudostable random variables   via functional equations
  In this paper we give a first attempt to define and study stable distributions with respect to the weak generalized convolution, focusing our attention on the symmetric weakly stable distribution. As in the case of the classical convolution, characterization of distributions stable in the sense of the weak generalized convolution depends on solving some functional equations in the class of characteristic functions. 
W. Jarczyk, J. Misiewicz