@article{JIS_2001__4_2_a4,
     author = {Puri,  Yash and Ward,  Thomas},
     title = {Arithmetic and growth of periodic orbits},
     journal = {Journal of integer sequences},
     year = {2001},
     volume = {4},
     number = {2},
     zbl = {1004.11013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2001__4_2_a4/}
}