@article{10_1017_S0017089500031207,
     author = {Cohn, J. H. E.},
     title = {Perfect {Pell} {Powers}},
     journal = {Glasgow mathematical journal},
     pages = {19--20},
     year = {1996},
     volume = {38},
     number = {1},
     doi = {10.1017/S0017089500031207},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500031207/}
}