  We propose a bootstrap method for approximating the long-range terms in the
Contractor Renormalization (CORE) method. The idea is tested on the 2-D
Heisenberg antiferromagnet and the frustrated J_2-J_1 model. We obtain
renormalization group flows that directly reveal the Neel phase of the
unfrustrated HAF and the existence of a phase transition in the J_2-J_1 model
for weak frustration. However, we find that this bootstrap method is dependent
on blocking and truncation schemes. For this reason, we discuss these
dependencies and unresolved issues that researchers who use this approach must
consider.
