@incollection{AST_1977__41-42__255_0,
     author = {Pintz, J.},
     title = {On the sign changes of $\pi (x) - \ell i x$},
     booktitle = {Journ\'ees arithm\'etiques de Caen},
     series = {Ast\'erisque},
     pages = {255--265},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {41-42},
     year = {1977},
     zbl = {0356.10033},
     mrnumber = {447151},
     language = {en},
     url = {http://www.numdam.org/item/AST_1977__41-42__255_0/}
}