@article{MZ_1979__165_172801,
     author = {Per Sj\"olin},
     title = {An {Hp} {Inequality} for {Strongly} {Singular} {Integrals.}},
     journal = {Mathematische Zeitschrift},
     pages = {231--238},
     publisher = {mathdoc},
     volume = {165},
     year = {1979},
     zbl = {0378.47028},
     url = {http://geodesic.mathdoc.fr/item/MZ_1979__165_172801/}
}