1. R. C. Vaughan,The Hardy-Littlewood Method, Cambridge Univ. Press, Cambridge (1981).
2. Yu. V. Linnik, “Additive problems involving squares, cubes and almost primes”,Acta Arithm.,21, 413–422 (1972).
3. C. Hooley, “On a new approach to various problems of Waring's type,” in:Recent Progress in Analytic Number Theory I, London (1981), pp. 127–191.
4. Yu. V. Linnik, “On the representation of large numbers as sums of seven cubes”,Mat. Sb.,12, No. 2, 218–224 (1943).
5. W. Duke, “Hyperbolic distribution problems and half-integral weight Maass forms”,Invent. Math.,92, 73–90 (1988).