@article{PIM_1971_N_S_12_26_a9,
     author = {Jovan D. Ke\v{c}ki\'c},
     title = {Clairaut's {Equations} {Of} {Higher} {Order}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {63 },
     publisher = {mathdoc},
     volume = {_N_S_12},
     number = {26},
     year = {1971},
     url = {http://geodesic.mathdoc.fr/item/PIM_1971_N_S_12_26_a9/}
}