@article{MABA_1990_4_1_a9,
     author = {Vesselin Petkov and Tsviatko Rangelov},
     title = {Leading {Singularity} of the {Scattering} {Kernel} for {Moving} {Obstacles}},
     journal = {Mathematica balkanica},
     pages = {91},
     publisher = {mathdoc},
     volume = {4},
     number = {1},
     year = {1990},
     url = {http://geodesic.mathdoc.fr/item/MABA_1990_4_1_a9/}
}