@article{NUMA_1973__21_132239,
     author = {Bertil Gustafsson},
     title = {A {Numerical} {Method} for {Solving} {Singular} {Boundary} {Value} {Problems.}},
     journal = {Numerische Mathematik},
     pages = {328--344},
     publisher = {mathdoc},
     volume = {21},
     year = {1973},
     zbl = {0255.65032},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1973__21_132239/}
}