Brown, S, Matta, A, Gruber, HE, Hanley, EN, Erwin, M, Roberts, S, Little, CB, Melrose, J, "Cell Clusters Are Indicative of Stem Cell Activity in the Degenerate Intervertebral Disc: Can Their Properties Be Manipulated to Improve Intrinsic Repair of the Disc?", Stem Cells and Development, 2018