1. V.A. Demjanenko: L. Euler’s Conjecture, Acta arithmetica 25, 1973–1974, 127–135.
2. Noam Elkies: Ort A
4
+ B4 + C4 = D4, Mathematics of Computation 51, 1988, 825–835.
3. L.J. Lander und T.R. Parkin: Counterexamples to Euler’s Conjecture on Sums ofLike Powers, Bulletin of the American Mathematical Society 72, 1966, 1079.
4. L.J. Mordell: Diophantine Equations, New York, Academic Press 1969.
5. Paulo Ribenboim: 13 Lectures on Fermat’s Last Theorem, New York, Springer 1979.