The first spectroscopic dust reverberation programme on active galactic nuclei: the torus in NGC 5548

H. Landt, M.~J. Ward, D. Kynoch, C. Packham, G.~J. Ferland, A. Lawrence, J. -U. Pott, J. Esser, K. Horne, D.~A. Starkey, D. Malhotra, M.~M. Fausnaugh, B.~M. Peterson, R.~J. Wilman, R.~A. Riffel, T. Storchi-Bergmann, A.~J. Barth, C. Villforth, H. Winkler