@article{CC_2008_37_2_a3,
     author = {Dmitruk, Andrei V.},
     title = {Jacobi type conditions for singular extremals},
     journal = {Control and Cybernetics},
     pages = {285--306},
     publisher = {mathdoc},
     volume = {37},
     number = {2},
     year = {2008},
     zbl = {1235.49043},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CC_2008_37_2_a3/}
}