@article{CM_1995__97_1-2_173_0,
     author = {Nygaard, Niels O.},
     title = {Construction of some classes in the cohomology of {Siegel} modular threefolds},
     journal = {Compositio Mathematica},
     pages = {173--186},
     publisher = {Kluwer Academic Publishers},
     volume = {97},
     number = {1-2},
     year = {1995},
     mrnumber = {1355124},
     zbl = {0838.11046},
     language = {en},
     url = {http://www.numdam.org/item/CM_1995__97_1-2_173_0/}
}