@article{10_4064_ba62_2_7,
     author = {Adam Os\k{e}kowski},
     title = {Sharp {Weak-Type} {Inequality} for the {Haar} {System,} {Harmonic} {Functions} and {Martingales}},
     journal = {Bulletin of the Polish Academy of Sciences. Mathematics},
     pages = {187--196},
     publisher = {mathdoc},
     volume = {62},
     number = {2},
     year = {2014},
     doi = {10.4064/ba62-2-7},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/ba62-2-7/}
}