@article{10_4064_sm_49_2_185_194,
     author = {Miguel de Guzm\'an},
     title = {An inequality for the {Hardy-Littlewood} maximal operator with respect to a product of differentiation bases},
     journal = {Studia Mathematica},
     pages = {185--194},
     publisher = {mathdoc},
     volume = {49},
     number = {2},
     year = {1973},
     doi = {10.4064/sm-49-2-185-194},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-49-2-185-194/}
}