Atek, H., Richard, J., Kneib, J.-P., Clément, B., Egami, E., Ebeling, H., Jauzac, M., Jullo, E., Laporte, N., Limousin, M., Natarajan, P., "Probing the z > 6 Universe with the First Hubble Frontier Fields Cluster A2744", Astrophysical Journal, 2014