@article{GAMA_1968_1968_1_a4,
     author = {Fern\'andez Vi\~na, J. A.},
     title = {La noci\'on de orientaci\'on.},
     journal = {Gaceta matem\'atica},
     pages = {67-71},
     publisher = {mathdoc},
     volume = {20},
     number = {3-4},
     year = {1968},
     language = {es},
     url = {http://geodesic.mathdoc.fr/item/GAMA_1968_1968_1_a4/}
}