@article{DA_1977_16_a1,
     author = {L. T. Ashchepkov and N. V. Tarasenko},
     title = {On the conditions for second order optimality in discrete and continuous systems and connections between them},
     journal = {Diskretnyj analiz i issledovanie operacij},
     pages = {11--19},
     publisher = {mathdoc},
     number = {16},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DA_1977_16_a1/}
}