Below is the ascii version of the abstract for 04-127. The html version should be ready soon.

Taksu Cheon and Pavel Exner
An approximation to delta' couplings on graphs
(26K, LaTeX)

ABSTRACT.  We discuss a general parametrization for
vertices of quantum graphs and show, in particular, how the
delta'_s and delta' coupling at an n edge vertex can be
approximated by means of n+1 couplings of the delta type
provided the latter are properly scaled.