@article{10_4064_aa_11_4_397_410,
     author = {R. Lehman},
     title = {On the difference \ensuremath{\pi}(x) - li(x)},
     journal = {Acta Arithmetica},
     pages = {397--410},
     publisher = {mathdoc},
     volume = {11},
     number = {4},
     year = {1965},
     doi = {10.4064/aa-11-4-397-410},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-11-4-397-410/}
}