TY  - JOUR
A1  - Neidhardt, Hagen
A1  - Zagrebnov, Valentin A.
T1  - On the right Hamiltonian for the singular perturbations : general theory
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Neidhardt, Hagen
A1  - Zagrebnov, Valentin A.
T1  - Fractional powers of self-adjoint operators and Trotter-Kato product formula
Y1  - 1997
ER  -