  We present our investigation on the effect of warps on the extraction of
rotation curves in edge-on galaxies. The method to derive the rotation curve
from the position-velocity diagram in warped edge-on systems yields
underestimated velocities, and the tilted-ring model is not reliable in highly
inclined, poorly resolved galaxies. In a warped system the kinematical major
axis is different from the optical major axis. While this is generally a limit
in optical slit spectroscopy, in the HI emission which extends far from the
optical body where self-gravity is weaker and the effect of warping is more
pronounced, this represents a severe effect to be considered in the procedure
to extract the rotation curve. We propose a new approach to extract the
rotation curve in highly inclined, warped galaxies. Based on this method we are
able to trace accurately the frequency of peculiarities in our sample of Thick
Boxy Bulge (TBB) galaxies. We report an increasing trend of kinematical
lopsidedness from spheroidal bulge galaxies towards TBB galaxies. Concerning
the question whether interactions contribute significantly to the bar formation
and to the subsequent evolution in a box/peanut (b/p) structure, we confirm
these theoretical predictions. Based on our sample, galaxy interaction is the
likely formation mechanism to trigger bars in TBB galaxies.
