@article{EXMATH_1989_1989_1_a11,
     author = {Okrasinski, W.},
     title = {Ecuaciones no lineales de {Volterra} y aplicaciones f{\'\i}sicas. {[Ap\'endice:} {Sobre} una extensi\'on de la condici\'on de {Gripenberg].}},
     journal = {Extracta mathematicae},
     pages = {51-80},
     publisher = {mathdoc},
     volume = {4},
     number = {2},
     year = {1989},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EXMATH_1989_1989_1_a11/}
}