@article{ASENS_1997_4_30_4_417_0,
     author = {Gordon, Carolyn S. and Mao, Yiping and Schueth, Dorothee},
     title = {Symplectic rigidity of geodesic flows on two-step nilmanifolds},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {417--427},
     publisher = {Elsevier},
     volume = {Ser. 4, 30},
     number = {4},
     year = {1997},
     doi = {10.1016/s0012-9593(97)89927-2},
     mrnumber = {98g:53077},
     zbl = {0897.53033},
     language = {en},
     url = {http://www.numdam.org/articles/10.1016/s0012-9593(97)89927-2/}
}