@article{1077375083, author = {Mordell, L. J.}, title = {On the congruence $ax^3+by^3+cz^3+dxyz \equiv n(\mod p)$}, journal = {Duke Math. J.}, volume = {31}, number = {1}, year = {1964}, pages = { 123-126}, language = {en}, url = {http://dml.mathdoc.fr/item/1077375083} }
Mordell, L. J. On the congruence $ax^3+by^3+cz^3+dxyz \equiv n(\mod p)$. Duke Math. J., Tome 31 (1964) no. 1, pp. 123-126. http://gdmltest.u-ga.fr/item/1077375083/