@article{DAN_1970_193_5_a1,
     author = {K. I. Babenko},
     title = {On the theory of the second variation of functionals on the class $S$ of univalent functions},
     journal = {Doklady Akademii Nauk},
     pages = {970--973},
     publisher = {mathdoc},
     volume = {193},
     number = {5},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_193_5_a1/}
}