@article{EJMCA_2018_6_2_a0,
     author = {V. I. Berdyshev and V. B. Kostousov},
     title = {Extremal problems of navigation by geophysical fields},
     journal = {Eurasian journal of mathematical and computer applications},
     pages = {4--18},
     publisher = {mathdoc},
     volume = {6},
     number = {2},
     year = {2018},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJMCA_2018_6_2_a0/}
}