Abstract
We study periodic chain clusters comprising equal numbers of
two-dimensional bubbles of two different areas, with at most
four bubbles per period. The cluster energies are calculated as
a function of the ratio λ of bubble areas and of the
imposed strain 
. We identify the clusters of lowest
energy for each (λ,), and obtain the Young's
moduli of all clusters in their unstrained state. An
approximately linear correlation has been found between the
Young's moduli and the cluster binding energy per unit area,
similar to that which holds for crystalline solids (e.g. metals).