Mejdi Azaïez Ralf Gruber M. O. Deville E. H. Mund On a Stable Spectral Method for the grad(div) Eigenvalue Problem. 41-50 2006 27 J. Sci. Comput. 1-3 http://dx.doi.org/10.1007/s10915-005-9037-9 db/journals/jscic/jscic27.html#AzaiezGDM06