@article{10_4064_cm100_1_8,
     author = {Florian Luca and P. G. Walsh},
     title = {On the number of nonquadratic residues
 which are not primitive roots},
     journal = {Colloquium Mathematicum},
     pages = {91--93},
     publisher = {mathdoc},
     volume = {100},
     number = {1},
     year = {2004},
     doi = {10.4064/cm100-1-8},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm100-1-8/}
}