@article{ZVMMF_2009_49_6_a5,
     author = {M. I. Sumin},
     title = {The first variation and {Pontryagin's} maximum principle in optimal control for partial differential equations},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {998--1020},
     publisher = {mathdoc},
     volume = {49},
     number = {6},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_2009_49_6_a5/}
}