@article{DAN_1981_261_6_a11,
     author = {A. N. Tikhonov and V. Ya. Arsenin and V. I. Pavlov and A. Kh. Pergament},
     title = {On the beam divergence in a high power
},
     journal = {Doklady Akademii Nauk},
     pages = {1333--1336},
     publisher = {mathdoc},
     volume = {261},
     number = {6},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1981_261_6_a11/}
}