1. V. D. Charushnikov, ?Universally optimal cubature formulae,? Dokl. Akad. Nauk SSSR,191, No. 4, 776?778 (1970).
2. V. D. Charushnikov, ?The optimization of a cubature process in spaces of periodic functions,? Sibirsk. Matem. Zh.,12, No. 1, 237?240 (1971).
3. V. D. Charushnikov and T. Kh. Shapirov, ?Universal cubature formulae, close to optimal,? Vopros. Vychisl. i Prikladnoi Matem., No. 38, Tashkent (1970).
4. I. Babushka, ?Über universal optimale Quadratur Formeln,? Apl. Math.,13, No. 4, 304?338 (1968); No. 5, 338?403 (1968).
5. L. S. Sobolev, Lectures on the Theory of Cubature Formulae [in Russian], Part II, Novosibirsk (1965).