  Recent low-temperature scanning tunnelling spectroscopy experiments on the
surface of BSCCO-2212 have revealed a strong positive correlation between the
position of localized resonances at -960 meV identified with interstitial
oxygen dopants and the size of the local spectral gap. We review efforts to
understand these correlations within a model where the dopants modulate the
pair interaction on an atomic scale. We provide further evidence for this model
by comparing the correlations between the dopants and the local density of
states with experimental results.
