@article{MM2_1973__11_154222,
     author = {W. Roelcke and J. Elstrodt},
     title = {\"Uber das wesentliche {Spektrum} zum {Eigenwertproblem} der automorphen {Formen.}},
     journal = {Manuscripta mathematica},
     pages = {391--406},
     publisher = {mathdoc},
     volume = {11},
     year = {1973},
     zbl = {0275.10016},
     url = {http://geodesic.mathdoc.fr/item/MM2_1973__11_154222/}
}