@article{10_4064_aa_19_3_215_222,
     author = {Charles Parry},
     title = {On a problem of {Schinzel} concerning principal divisors in arithmetic progressions},
     journal = {Acta Arithmetica},
     pages = {215--222},
     publisher = {mathdoc},
     volume = {19},
     number = {3},
     year = {1971},
     doi = {10.4064/aa-19-3-215-222},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-19-3-215-222/}
}