@article{MZ_1991__208_3_174299,
     author = {Rafael Oswaldo Ruggiero},
     title = {On the creation of conjugate points.},
     journal = {Mathematische Zeitschrift},
     pages = {41--56},
     publisher = {mathdoc},
     volume = {208},
     number = {3},
     year = {1991},
     zbl = {0749.58042},
     url = {http://geodesic.mathdoc.fr/item/MZ_1991__208_3_174299/}
}