@article{PMIHES_1980__51__137_0,
     author = {Katok, Anatole},
     title = {Lyapunov exponents, entropy and periodic orbits for diffeomorphisms},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     pages = {137--173},
     publisher = {Institut des Hautes \'Etudes Scientifiques},
     volume = {51},
     year = {1980},
     mrnumber = {573822},
     zbl = {0445.58015},
     language = {en},
     url = {http://archive.numdam.org/item/PMIHES_1980__51__137_0/}
}