@article{EXMATH_1995_1995_1_a25,
     author = {Berk, R. H. and Nogales, A. G. and Oyola, J. A.},
     title = {Algunos contraejemplos relativos a suficiencia e invariancia.},
     journal = {Extracta mathematicae},
     pages = {52-55},
     publisher = {mathdoc},
     volume = {10},
     number = {1},
     year = {1995},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EXMATH_1995_1995_1_a25/}
}