@article{RCM_1987__21_1_181779,
     author = {Paulo R. Rodrigues and Manuel de Leon de},
     title = {Comments {On} {The} {Canonical} {Formalism} {Of} {Time-Dependent} {Higher} {Order} {Lagrangians.}},
     journal = {Revista colombiana de matematicas},
     pages = {47--64},
     publisher = {mathdoc},
     volume = {21},
     number = {1},
     year = {1987},
     zbl = {0671.58014},
     url = {http://geodesic.mathdoc.fr/item/RCM_1987__21_1_181779/}
}