  We derive analytical forms for non-flow contributions from cluster
correlation to two-particle elliptic flow (v2{2}) measure. We also derive an
analytical form for jet-correlation flow-background with the same cluster
approach. We argue that the elliptic flow v2 parameter to be used in
jet-correlation background is that from two-particle method excluding non-flow
correlations unrelated to the reaction plane, but including cross-terms between
cluster correlation and cluster flow. We verify our result with Monte Carlo
simulations. We discuss how one may obtain the v2 parameter for jet-correlation
background experimentally.
