@article{RMC_2007_2007_1_a15,
     author = {Ozawa, Makoto and  Tsutsumi, Yukihiro},
     title = {Primitive spatial graphs and graph minors.},
     journal = {Revista matem\'atica complutense},
     pages = {391-406},
     publisher = {mathdoc},
     volume = {20},
     number = {2},
     year = {2007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RMC_2007_2007_1_a15/}
}