Automatic domain decomposition on unstructured grids (DOUG). - M. J. Hagger (Adv. Comput. Math., 1998)

Unstructured Additive Schwarz-Conjugate Gradient Method for Elliptic Problems with Highly Discontinuous Coefficients. - Ian G. Graham; M. J. Hagger (SIAM J. Sci. Comput., 1999)