G. Zambonin, M. Grano, G. Greco, R. O. C. Oreffo, and J. T. Triffit, “Hydroxyapatite coated with insulin-like growth factor 1 (IGF1) stimulates human osteoblast activity in vitro”, ActaO, vol. 70, no. 2, pp. 217–220, Jan. 1999.