@article{IM2_1997_61_1_a0,
     author = {V. I. Burenkov and A. L. Gorbunov},
     title = {Exact bounds for the minimum norm of extension operators for {Sobolev} spaces},
     journal = {Izvestiya. Mathematics },
     pages = {1--43},
     publisher = {mathdoc},
     volume = {61},
     number = {1},
     year = {1997},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1997_61_1_a0/}
}