National Osteoporosis Society practical clinical guideline on vitamin D and bone health. Issue 2 (February 2015) - Francis, R.M.; Aspray, T.J.; Bowring, C.E.; Fraser, W.D.; Gittoes, N.J.; Javaid, M.K.; Macdonald, H.M.; Patel, S.; Selby, P.L.; Tanna, N.