New segmental long bone defect model in sheep: quantitative analysis of healing with dual energy x-ray absorptiometry. - den Boer,F.C.; Patka,P.; Bakker,F.C.; Wippermann,B.W.; Lingen,A van.; Vink,G.Q.; Boshuizen,K.; Haarman,H.J. (J Orthop Res, 1999)