@article{MAN_1904__58_158117,
     author = {G. Bli{\ss}},
     title = {Jacobi's {Criterion} when both end-points are variable},
     journal = {Mathematische Annalen},
     pages = {70--80},
     publisher = {mathdoc},
     volume = {58},
     year = {1904},
     zbl = {34.0402.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1904__58_158117/}
}