@article{10_4007_annals_2005_161_397,
     author = {Bernard Host and Bryna R. Kra},
     title = {Nonconventional ergodic averages and nilmanifolds},
     journal = {Annals of mathematics},
     pages = {397--488},
     year = {2005},
     volume = {161},
     number = {1},
     doi = {10.4007/annals.2005.161.397},
     mrnumber = {2150389},
     zbl = {1077.37002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4007/annals.2005.161.397/}
}