  When integrals in the standard Tremaine-Weinberg method are evaluated for the
case of a realistic model of a doubly barred galaxy, their modifications
introduced by the second rotating pattern are in accord with what can be
derived from a simple extension of that method, based on separation of tracer's
density. This extension yields a qualitative argument that discriminates
between prograde and retrograde inner bars. However, the estimate of the value
of inner bar's pattern speed requires further assumptions. When this extension
of the Tremaine-Weinberg method is applied to the recent observation of the
doubly barred galaxy NGC 2950, it indicates that the inner bar there is
counter-rotating, possibly with the pattern speed of -140 +/- 50 km/s/arcsec.
The occurrence of counter-rotating inner bars can constrain theories of galaxy
formation.
