1. Equations of the form x2 − Dy2 = 2z2;Cohen;Math. Student,1982
2. On Legendre's equation ax2 + by2 + cz2 = 0;Hudson;J. Number Theory,1983
3. Diophantine equations;Mordell,1969
4. On the diophantine equation ax2 + by2 + cz2 = 0;Skolem;Univ. Roma 1st. Naz. Alta Mat. Appl.,1952
5. Integral quadratic forms;Watson,1960