@article{ZNSL_1991_190_a6,
     author = {M. A. Skopina},
     title = {On the almost everywhere convergence of {Marcinkiewicz} sums of double {Fourier} series},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {148--156},
     year = {1991},
     volume = {190},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1991_190_a6/}
}