@article{JRAM_1986__366_152814,
     author = {G. Harder and R.P. Langlands},
     title = {Algebraische {Zyklen} auf {Hilbert-Blumenthal-Fl\"achen.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {53--120},
     publisher = {mathdoc},
     volume = {366},
     year = {1986},
     zbl = {0575.14004},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1986__366_152814/}
}