@article{VMP_2006_7_2_a7,
     author = {B. N. Ivanov},
     title = {Enclosure structures of equal level line fields in the gradient filling problem},
     journal = {Numerical methods and programming},
     pages = {30--40},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMP_2006_7_2_a7/}
}