@article{MS2_1974__35_166394,
     author = {Kenneth S. Williams},
     title = {3 as a {Ninth} {Power} (mod p).},
     journal = {Mathematica Scandinavica},
     pages = {309--317},
     publisher = {mathdoc},
     volume = {35},
     year = {1974},
     zbl = {0297.10002},
     url = {http://geodesic.mathdoc.fr/item/MS2_1974__35_166394/}
}