B. J. Birch and N. M. Stephens, The parity of the rank of the Mordell-Weil group,
Topology 5 (1966) 295--299.
H. Cohen, Number Theory volume I, Tools and Diophantine Equations, Springer, New York, 2007.
A. Choudhry, The Diophantine equation
A^{4} +
B^{4} =
C^{4 }+
D^{4},
Indian J. Pure Appl. Math. 22 (1991), no. 1, 9--11.
D. A. Cox, Primes of the Form
x^{2} +
ny^{2}: Fermat, Class Field Theory, and Complex Multiplication, Pure and Applied Mathematics, John Wiley & Sons, 2011.
L. E. Dickson, History of the Theory of numbers, 2, Reprinted by chelsea, New York, 1971.
L. Euler, Novi Comm. Acad Petrop., v. 17, p. 64. 1772.
L. Euler, Nova Acta Acad, Petrop., v. 13, ad annos 1795-6, 1802, 1778.
L. Euler, Mem. Acad. Sc. St. Petersb., v.11, 1830.
G. H. Hardy and E. M. Wright, An introduction to the theory of numbers. Sixth edition. Revised by D. R. Heath-Brown and J. H. Silverman, With a foreword by Andrew Wiles, Oxford University Press, Oxford, 2008.
F. A. Izadi, F. Khoshnam and K. Nabardi, Sums of two biquadrates and elliptic curves of rank ≥4,
Math. J. Okayama Univ. 56 (2014) 51--63.
G. H. Hardy, Ramanujan: Twelve Lectures on Subjected by His Life and Work, 3rd ed New York, Chelsea, 1999.
L. J. Lander, and T. R. Parkin, Equal sums of biquadrates,
Math. Comp. 20 (1966) 450--451.
L. J. Lander, T. R. Parkin, and J. L. Selfridge, A Survey of equal sums of like powers,
Math. Comp. 21 (1967) 446--459.
P. Monsky, Mock Heegner Points and Congruent Numbers,
Math. Z. 204 (1990), no. 1, 45--67.
K. Ono, Twists Of Elliptic Curves,
Compositio Math. 106 (1997), no. 3, 349--360.
K. Ono and T. Ono, Quadratic Form And Elliptic Curves III,
Proc. Japan Acad. Ser. A Math. Sci. 72 (1996), no. 9, 204--205.
P. Serf, Congruent Numbers and Elliptic Curves, Computational Number Theory (Debrecen, 1989), 227--238, de Gruyter, Berlin, 1991.
SAGE Software,
Version 4.3.5, http://sagemath.org.
J. H. Silverman, The Arithmetic of Elliptic curves, Springer-Verlag, New York, 1986.
J. H. Silverman, A Friendly Introduction to Number Theory, Springer-Verlag, New York, 2001.
A. Zajta, Solutions of the Diophantine equation
A^{4} +
B^{4} =
C^{4 }+
D^{4},
Math. Comp. 41 (1983), no. 164, 635--659.