Application of Colombeau's Generalized Functions to Cosmological Models   with Signature Change
  Colombeau's generalized functions are used to adapt the distributional approach to singular hypersurfaces in general relativity with signature change. Equations governing the dynamics of singular hypersurface is obtained and it is shown that the stress-energy tensor of the surface can be non-vanishing. 
Reza Mansouri and Kourosh Nozari