@article{EJDE_2006__2006__a28,
     author = {Umeda,  Tomio},
     title = {Generalized eigenfunctions of relativistic {Schr\"odinger} operators. {I}},
     journal = {Electronic journal of differential equations},
     year = {2006},
     volume = {2006},
     zbl = {1118.35051},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2006__2006__a28/}
}