@article{RM_2013_68_5_a6,
     author = {R. G. Novikov and I. A. Taimanov},
     title = {The {Moutard} transformation and two-dimensional multipoint delta-type potentials},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {957--959},
     year = {2013},
     volume = {68},
     number = {5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_2013_68_5_a6/}
}