Monopole and dipole layers in curved spacetimes: formalism and examples
  The discontinuities of electromagnetic test fields generated by general layers of electric and magnetic monopoles and dipoles are investigated in general curved spacetimes. The equivalence of electric currents and magnetic dipoles is discussed. The results are used to describe exact "Schwarzschild disk" solutions endowed with such sources. The resulting distributions of charge and dipole densities on the disks are corroborated using the membrane paradigm. 
Norman G\"urlebeck, Ji\v{r}\'i Bi\v{c}\'ak, Antonio C.   Guti\'errez-Pi\~neres
gr-qc