@article{IM2_1997_61_6_a4,
     author = {A. O. Ivanov and A. A. Tuzhilin},
     title = {The geometry of minimal networks with a~given topology and a~fixed boundary},
     journal = {Izvestiya. Mathematics},
     pages = {1231--1263},
     year = {1997},
     volume = {61},
     number = {6},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1997_61_6_a4/}
}