CMBPol Mission Concept Study: Probing Inflation with CMB Polarization by Baumann, D, Jackson, MG, Adshead, P, Amblard, A, Ashoorioon, A, Bartolo, N, Bean, R, Beltran, M, Bernardis, F, Bird, S, Chen, X, Chung, D, Colombo, L, Cooray, A, Creminelli, P, Dodelson, S, Dunkley, J, Dvorkin, C, Easther, R, Finelli, F, Flauger, R, Hertzberg, M, Jones-Smith, K, Kachru, S, Kadota, K