@article{IM_1995__119_3_144254,
     author = {E.M. Stein and Detlef M\"uller and F. Ricci},
     title = {Marcinkiewicz multipliers and multi-parameter structure on {Heisenberg} (-type) groups, {I.}},
     journal = {Inventiones mathematicae},
     pages = {199--234},
     publisher = {mathdoc},
     volume = {119},
     number = {3},
     year = {1995},
     zbl = {0857.43012},
     url = {http://geodesic.mathdoc.fr/item/IM_1995__119_3_144254/}
}