  The form factor of a quantum graph is a function measuring correlations
within the spectrum of the graph. It can be expressed as a double sum over the
periodic orbits on the graph. We propose a scheme which allows one to evaluate
the periodic orbit sum for a special family of graphs and thus to recover the
expression for the form factor predicted by the Random Matrix Theory. The
scheme, although producing the expected answer, undercounts orbits of a certain
structure, raising doubts about an analogous summation recently proposed for
quantum billiards.
