@article{ZNSL_1982_107_a17,
     author = {J. B. Farforovskaja},
     title = {On the difference $f(B)-f(A)$ for unbounded self-adjoint operators in the perturbation theory},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {213--221},
     publisher = {mathdoc},
     volume = {107},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1982_107_a17/}
}