the Frequency Theorem for nonperiodic systems
Fabbri and Russell Johnson,
Bifurcations and Control, 233-241,
in Control and Information Sciences 273,
Colonius, Springer-Verlag, 2002.
methods of the theory of nonautonomous linear
namely exponential dichotomies and rotation numbers, some
Yakubovich's Frequency Theorem from periodic control systems are
generalized to systems with bounded measurable coefficients.