@incollection{MSMF_1971__25__159_0,
     author = {Narkiewicz, W.},
     title = {Some unsolved problems},
     booktitle = {Colloque de th\'eorie des nombres (Bordeaux, 1969)},
     series = {M\'emoires de la Soci\'et\'e Math\'ematique de France},
     pages = {159--164},
     publisher = {Soci\'et\'e math\'ematique de France},
     number = {25},
     year = {1971},
     doi = {10.24033/msmf.48},
     mrnumber = {57 #5943},
     zbl = {0217.03102},
     url = {http://www.numdam.org/articles/10.24033/msmf.48/}
}