2 citations to https://www.mathnet.ru/rus/cmfd234

1. K. N. Zhuikov, “Index of Differential-Difference Operators on an Infinite Cylinder”, Russ. J. Math. Phys., 29:2 (2022), 280  
2. Gorokhovsky A., de Kleijn N., Nest R., “Equivariant Algebraic Index Theorem”, J. Inst. Math. Jussieu, 20:3 (2021), PII S1474748019000380, 929–955