@article{MABA_1991_5_3_a0,
     author = {R. P. Ivanov},
     title = {On {Viable} {Solutions} of {Feedback} {Controlled} {System}},
     journal = {Mathematica balkanica},
     pages = {177},
     publisher = {mathdoc},
     volume = {5},
     number = {3},
     year = {1991},
     url = {http://geodesic.mathdoc.fr/item/MABA_1991_5_3_a0/}
}