Glucosamine and chondroitin for knee osteoarthritis: a double-blind randomised placebo-controlled clinical trial evaluating single and combination regimens by Fransen, M, Agaliotis, M, Nairn, L, Votrubec, M, Bridgett, L, Su, S, Jan, S, March, L, Edmonds, J, Norton, R, Woodward, M, Day, R, Agaliotis, M, Bridgett, L, Buckland-Wright, C, Bridges-Webb, C, Day, R, Edmonds, J, Jan, S, Heritier, S, Fransen, M, Jones, G, March, L, Nairn, L, Norton, R