@article{AM2_1987__34_137243,
     author = {Ludger Kaup and K.-H. Fieseler},
     title = {On the hard {Lefschetz} theorem in intersection homology for complex varieties with isolated singularities.},
     journal = {Aequationes mathematicae},
     pages = {240--263},
     publisher = {mathdoc},
     volume = {34},
     year = {1987},
     zbl = {0648.14009},
     url = {http://geodesic.mathdoc.fr/item/AM2_1987__34_137243/}
}