@article{SM_1993_74_2_a15,
     author = {A. O. Ivanov and A. A. Tuzhilin},
     title = {The {Steiner} problem in the plane or in plane minimal nets},
     journal = {Sbornik. Mathematics},
     pages = {555--582},
     publisher = {mathdoc},
     volume = {74},
     number = {2},
     year = {1993},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1993_74_2_a15/}
}