@article{JLT_2004_14_1_JLT_2004_14_1_a10,
     author = {D. Pickrell},
     title = {H\protect\textsuperscript{4}(BK, {Z)} and {Operator} {Algebras}},
     journal = {Journal of Lie theory},
     pages = {199--213},
     publisher = {mathdoc},
     volume = {14},
     number = {1},
     year = {2004},
     url = {http://geodesic.mathdoc.fr/item/JLT_2004_14_1_JLT_2004_14_1_a10/}
}