@article{10_4064_aa_89_1_23_35,
     author = {A. van der Poorten and H. Williams},
     title = {On certain continued fraction expansions of fixed period length},
     journal = {Acta Arithmetica},
     pages = {23--35},
     publisher = {mathdoc},
     volume = {89},
     number = {1},
     year = {1999},
     doi = {10.4064/aa-89-1-23-35},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-89-1-23-35/}
}