Observational properties of massive black hole binary progenitorsR. Hainich, L. M. Oskinova, T. Shenar, P. Marchant, J. J. Eldridge, A. A. C. Sander, W.-R. Hamann, N. Langer and H. TodtA&A, 609 (2018) A94DOI: https://doi.org/10.1051/0004-6361/201731449
