TY  - JOUR
AU  - A. L. Likhtarnikov
AU  - V. A. Yakubovich
TI  - The frequency theorem for continuous one-parameter semigroups
JO  - Izvestiya. Mathematics 
PY  - 1977
SP  - 849
EP  - 864
VL  - 11
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1977_11_4_a7/
LA  - en
ID  - IM2_1977_11_4_a7
ER  -