HELIO: The Heliophysics Integrated Observatory - Bentley, R.D.; Csillaghy, A.; Aboudarham, J.; Jacquey, C.; Hapgood, M.A.; Bocchialini, K.; Messerotti, M.; Brooke, J.; Gallagher, P.; Fox, P.; Hurlburt, N.; Roberts, D.A.; et al. (Advances in Space Research, 2011)