@article{MM2_1990__66_1_155471,
     author = {Lothar G\"ottsche},
     title = {Betti numbers for the {Hilbert} function strata of the punctual {Hilbert} scheme in two variables.},
     journal = {Manuscripta mathematica},
     pages = {253--260},
     publisher = {mathdoc},
     volume = {66},
     number = {1},
     year = {1990},
     zbl = {0714.14004},
     url = {http://geodesic.mathdoc.fr/item/MM2_1990__66_1_155471/}
}