INDEX OF NONLOCAL ELLIPTIC OPERATORS OVER C*-ALGEBRAS Статья Savin A.Yu., Sternin B.Yu. Doklady Mathematics. Том 79. 2009. С. 369-372
SURGERY AND INDEX FORMULAS ON STRATIFIED MANIFOLDS Статья Savin A.Y., Sternin B.Y. Doklady Mathematics. Том 80. 2009. С. 521-524