1. 1. C. F. Gauss, Werke: (a) vol. I, pp. 445-449; (b) vol. II, pp. 67-92; (c) vol. X1, p. 571.
2. 2. C. G. Jacobi, Gesammelte Werke: (a) vol. VII, pp. 393-400; (b) vol. VI, pp. 254-274.
3. 3. V. A. Lebesgue: (a) J. Math. Pures Appl. vol. 2 (1837) pp. 253-292
4. (b) J. Math. Pures Appl. vol. 3 (1838) pp. 113-144.
5. Some problems of ‘Partitio Numerorum’: IV. The singular series in Waring’s Problem and the value of the number 𝐺(𝑘);Hardy, G. H.;Math. Z.,1922