Z. Lebens-Higgins, D.O. Scanlon, H. Paik, S. Sallis, Y. Nie, M. Uchida, N.F. Quackenbush, M.J. Wahila, G.E. Sterbinsky, D.A. Arena, J.C. Woicik, D.G. Schlom, and L.F.J. Piper, “Direct Observation of Electrostatically Driven Band Gap Renormalization in a Degenerate Perovskite Transparent Conducting Oxide,” Physical Review Letters 116 (2016) 027602-1 – 027602-5.