@article{RRACEFN_1980_1980_1_a12,
     author = {Gonz\'alez Velasco, Enrique A.},
     title = {Teor{\'\i}a cualitativa de sistemas {Hamiltonianos.}},
     journal = {Revista de la Real Academia de Ciencias Exactas, F{\'\i}sicas y Naturales},
     pages = {225-245},
     year = {1980},
     volume = {74},
     number = {2},
     language = {es},
     url = {http://geodesic.mathdoc.fr/item/RRACEFN_1980_1980_1_a12/}
}