@article{MEM_2010_39_1_a11,
     author = {Kutev, Nikolai and Milousheva, Velichka},
     title = {Complete {Integrability} of a {Nonlinear} {Elliptic} {System,} {Generating} {Bi-umbilical} {Foliated} {Semi-symmetric} {Hypersurfaces} in {R^4}},
     journal = {Mathematics and Education in Mathematics},
     pages = {141--148},
     publisher = {mathdoc},
     volume = {39},
     number = {1},
     year = {2010},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MEM_2010_39_1_a11/}
}