@article{MAN_1908__65_158359,
     author = {Philip E.B. Jourdain},
     title = {On those {Principles} of {Mechanics} which depend upon {Processes} of {Variation}},
     journal = {Mathematische Annalen},
     pages = {513--527},
     publisher = {mathdoc},
     volume = {65},
     year = {1908},
     zbl = {38.0695.02},
     url = {http://geodesic.mathdoc.fr/item/MAN_1908__65_158359/}
}