@article{10_4064_aa_7_2_107_119,
     author = {Stanis{\l}aw Knapowski},
     title = {On sign-changes of the difference \ensuremath{\pi}(x)-li(x)},
     journal = {Acta Arithmetica},
     pages = {107--119},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {1961},
     doi = {10.4064/aa-7-2-107-119},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-7-2-107-119/}
}