@article{MAN_1972__198_162302,
     author = {M. van der Put},
     title = {Difference {Equations} over p-adic {Fields.}},
     journal = {Mathematische Annalen},
     pages = {189--204},
     publisher = {mathdoc},
     volume = {198},
     year = {1972},
     zbl = {0239.46046},
     url = {http://geodesic.mathdoc.fr/item/MAN_1972__198_162302/}
}