@article{JRAM_1980__318_152261,
     author = {D.H. Lehmer and Emma Lehmer},
     title = {Picturesque exponential sums. {II:}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {1--19},
     publisher = {mathdoc},
     volume = {318},
     year = {1980},
     zbl = {0433.10025},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1980__318_152261/}
}