@article{MS2_1982__51_166801,
     author = {Calle Jacobsson},
     title = {On the double {Poincar\'e} series of the enveloping algebras of certain graded {Lie} algebras.},
     journal = {Mathematica Scandinavica},
     pages = {45--58},
     year = {1982},
     volume = {51},
     zbl = {0499.16018},
     url = {http://geodesic.mathdoc.fr/item/MS2_1982__51_166801/}
}