@article{FAA_1976_10_4_a14,
     author = {V. I. Plotnikov and V. I. Sumin},
     title = {The first variation and the associated problem in optimal control theory},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {95--96},
     publisher = {mathdoc},
     volume = {10},
     number = {4},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1976_10_4_a14/}
}