@misc{WM_1901_5_4-5-6_a3,
     title = {O warunkach dostatecznych w rachunku waryacyjnym},
     journal = {Wiadomo\'sci Matematyczne},
     pages = {179--210},
     year = {1901},
     volume = {5},
     number = {4-5-6},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/item/WM_1901_5_4-5-6_a3/}
}