@article{AIF_1981__31_4_115_0, author = {Mauceri, Giancarlo}, title = {Riesz means for the eigenfunction expansions for a class of hypo-elliptic differential operators}, journal = {Annales de l'Institut Fourier}, pages = {115--140}, publisher = {Institut Fourier}, volume = {31}, number = {4}, year = {1981}, doi = {10.5802/aif.851}, zbl = {0455.35039}, mrnumber = {84h:35125}, language = {en}, url = {http://archive.numdam.org/articles/10.5802/aif.851/} }