@article{SM_1990_67_2_a8,
     author = {I. A. Ikromov},
     title = {Invariant estimates of two-dimensional trigonometric integrals},
     journal = {Sbornik. Mathematics},
     pages = {473--488},
     year = {1990},
     volume = {67},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1990_67_2_a8/}
}