An example of the Heisenberg group
Journées équations aux dérivées partielles, (1982), article no. 15, 3 p.
@article{JEDP_1982____A15_0,
     author = {Stein, Elias M.},
     title = {An example of the Heisenberg group},
     journal = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     publisher = {Ecole polytechnique},
     year = {1982},
     zbl = {0497.35069},
     language = {en},
     url = {http://www.numdam.org/item/JEDP_1982____A15_0}
}
Stein, Elias M. An example of the Heisenberg group. Journées équations aux dérivées partielles,  (1982), article  no. 15, 3 p. http://www.numdam.org/item/JEDP_1982____A15_0/

[1] Folland and Stein : Comm. Pure and Applied Math. 27 (1974), 429-522. | MR 51 #3719 | Zbl 0293.35012

[2] Greiner, Kohn and Stein : Proc. Nat. Acad. Sci. 72 (1975), 3287-3289. | MR 52 #1043 | Zbl 0308.35017

[3] To appear.