Time-domain evidence for an excitonic insulatorS. Hellmann, T. Rohwer, M. Kalläne, K. Hanff, A. Carr, M. M. Murnane, H. C. Kapteyn, L. Kipp, M. Bauer and K. RossnagelEPJ Web of Conferences, 41 (2013) 03022DOI: https://doi.org/10.1051/epjconf/20134103022