@article{TM_2012_278_a17,
     author = {Nedyu Popivanov and Todor Popov and Rudolf Scherer},
     title = {Protter--Morawetz multidimensional problems},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {188--207},
     publisher = {mathdoc},
     volume = {278},
     year = {2012},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TM_2012_278_a17/}
}