1. Kovács, K., Abut some positive solutions of the Diophantine equation ∑l≤i≤j≤n=m, Publ. Math. Debrecen, 1992, 40: 207.
2. Cai Tian-Xin, On the Diophantine equation xy +yz +zx = m(I),Publ. Math. Dubrecen, 1994, 45: 131.
3. Al-zaid, H., Brindza, B., Pinter, A., On positive integer solutions of the equationxy + yz + zx = n, Canad. Math. Bull., 1996, 39: 199.
4. Cox, D. A., Prime of the Form r2 +ny 2, New York: John Wiley & Sons, 1989.
5. Louboutin, S., Minorations (sous 1’hypothese de Riemann générlisée) des nombres de classes des corps quadratiques imaginairess, application,C. R. Acad. Sci. Paris, 1990, 310: 795.