1. The Magma algebra system. I. The user language;Bosma;J. Symbolic Comput.,1997
2. On xa±yb±zc±wd=0, 1/a+1/b+1/c+1/d=1;Bremner;Int. J. Number Theory,2011
3. On the Diophantine equation A4+hB4=C4+hD4;Choudhry;Indian J. Pure Appl. Math.,1995
4. History of the Theory of Numbers, Vol. II: Diophantine Analysis;Dickson,2005
5. On A4+B4+C4=D4;Elkies;Math. Comp.,1988