@article{AM2_1979__19_136818,
     author = {Ronald Infante},
     title = {Strong normality and normality for difference fields {(Short} {Communication).}},
     journal = {Aequationes mathematicae},
     pages = {121--122},
     year = {1979},
     volume = {19},
     url = {http://geodesic.mathdoc.fr/item/AM2_1979__19_136818/}
}