@article{701671,
     title = {On local stability of differential (n-1) -- forms on an n-manifold with boundary},
     booktitle = {Proceedings of the 20th Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {2001},
     pages = {105-115},
     mrnumber = {MR1826683},
     zbl = {1002.58002},
     url = {http://dml.mathdoc.fr/item/701671}
}

Domitrz, Wojciech. On local stability of differential (n-1) – forms on an n-manifold with boundary, dans Proceedings of the 20th Winter School "Geometry and Physics", GDML_Books,  (2001), pp. 105-115. http://gdmltest.u-ga.fr/item/701671/